Attachment 36993 Details for Bug 28790 – Improve es2gears.c gears demo (version 2)

[patch] Improve es2gears.c gears demo (version 2)

es2gears-refactor2.patch (text/plain), 24.24 KB, created by Alexandros Frantzis on 2010-07-13 07:43:04 UTC

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Creator: Alexandros Frantzis

Created: 2010-07-13 07:43:04 UTC

Size: 24.24 KB

patch

obsolete

>--- demos/src/egl/opengles2/es2gears.c	2010-06-22 14:41:00.173055999 +0300
>+++ demos-es2gears-refactor/src/egl/opengles2/es2gears.c	2010-07-13 17:29:22.784047996 +0300
>@@ -23,18 +23,23 @@
>  * Ported to GLES2.
>  * Kristian HÃ¸gsberg <krh@bitplanet.net>
>  * May 3, 2010
>+ * 
>+ * Improve GLES2 port:
>+ *   * Refactor gear drawing.
>+ *   * Use correct normals for surfaces.
>+ *   * Improve shader.
>+ *   * Use perspective projection transformation.
>+ *   * Add FPS count.
>+ *   * Add comments.
>+ * Alexandros Frantzis <alexandros.frantzis@linaro.org>
>+ * Jul 13, 2010
>  */
> 
>-/*
>- * Command line options:
>- *    -info      print GL implementation information
>- *
>- */
>-
>-
> #define GL_GLEXT_PROTOTYPES
> #define EGL_EGLEXT_PROTOTYPES
> 
>+#define _GNU_SOURCE
>+
> #include <math.h>
> #include <stdlib.h>
> #include <stdio.h>
>@@ -46,135 +51,239 @@
> #include <EGL/eglext.h>
> #include "eglut.h"
> 
>+#define STRIPS_PER_TOOTH 7
>+#define VERTICES_PER_TOOTH 34
>+#define GEAR_VERTEX_STRIDE 6
>+
>+/**
>+ * Struct describing the vertices in triangle strip
>+ */
>+struct vertex_strip {
>+   /** The first vertex in the strip */
>+   GLint first;
>+   /** The number of consecutive vertices in the strip after the first */
>+   GLint count;
>+};
>+
>+/* Each vertex consist of GEAR_VERTEX_STRIDE GLfloat attributes */
>+typedef GLfloat GearVertex[GEAR_VERTEX_STRIDE];
>+
>+/**
>+ * Struct representing a gear.
>+ */
> struct gear {
>-   GLfloat *vertices;
>+   /** The array of vertices comprising the gear */
>+   GearVertex *vertices;
>+   /** The number of vertices comprising the gear */
>+   int nvertices;
>+   /** The array of triangle strips comprising the gear */
>+   struct vertex_strip *strips;
>+   /** The number of triangle strips comprising the gear */
>+   int nstrips;
>+   /** The Vertex Buffer Object holding the vertices in the graphics card */
>    GLuint vbo;
>-   int count;
> };
> 
>-static GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0;
>+/** The view rotation [x, y, z] */
>+static GLfloat view_rot[3] = { 20.0, 30.0, 0.0 };
>+/** The gears */
> static struct gear *gear1, *gear2, *gear3;
>+/** The current gear rotation angle */
> static GLfloat angle = 0.0;
>-static GLuint proj_location, light_location, color_location;
>-static GLfloat proj[16];
>+/** The location of the shader uniforms */
>+static GLuint ModelViewProjectionMatrix_location,
>+              NormalMatrix_location,
>+              LightSourcePosition_location,
>+              MaterialColor_location;
>+/** The projection matrix */
>+static GLfloat ProjectionMatrix[16];
>+/** The direction of the directional light for the scene */
>+static const GLfloat LightSourcePosition[4] = { 5.0, 5.0, 10.0, 1.0};
> 
>-static GLfloat *
>-vert(GLfloat *p, GLfloat x, GLfloat y, GLfloat z, GLfloat *n)
>+/** 
>+ * Fills a gear vertex.
>+ * 
>+ * @param v the vertex to fill
>+ * @param x the x coordinate
>+ * @param y the y coordinate
>+ * @param z the z coortinate
>+ * @param n pointer to the normal table 
>+ * 
>+ * @return the operation error code
>+ */
>+static GearVertex *
>+vert(GearVertex *v, GLfloat x, GLfloat y, GLfloat z, GLfloat n[3])
> {
>-   p[0] = x;
>-   p[1] = y;
>-   p[2] = z;
>-   p[3] = n[0];
>-   p[4] = n[1];
>-   p[5] = n[2];
>-
>-   return p + 6;
>-}
>-
>-/*  Draw a gear wheel.  You'll probably want to call this function when
>- *  building a display list since we do a lot of trig here.
>- * 
>- *  Input:  inner_radius - radius of hole at center
>- *          outer_radius - radius at center of teeth
>- *          width - width of gear
>- *          teeth - number of teeth
>- *          tooth_depth - depth of tooth
>+   v[0][0] = x;
>+   v[0][1] = y;
>+   v[0][2] = z;
>+   v[0][3] = n[0];
>+   v[0][4] = n[1];
>+   v[0][5] = n[2];
>+
>+   return v + 1;
>+}
>+
>+/**
>+ *  Create a gear wheel.
>+ * 
>+ *  @param inner_radius radius of hole at center
>+ *  @param outer_radius radius at center of teeth
>+ *  @param width width of gear
>+ *  @param teeth number of teeth
>+ *  @param tooth_depth depth of tooth
>+ *  
>+ *  @return pointer to the constructed struct gear
>  */
> static struct gear *
>-gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
>-     GLint teeth, GLfloat tooth_depth)
>+create_gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
>+      GLint teeth, GLfloat tooth_depth)
> {
>-   GLint i;
>    GLfloat r0, r1, r2;
>    GLfloat da;
>-   GLfloat *p, *v;
>+   GearVertex *v;
>    struct gear *gear;
>    double s[5], c[5];
>-   GLfloat verts[3 * 14], normal[3];
>-   const int tris_per_tooth = 20;
>+   GLfloat normal[3];
>+   int cur_strip = 0;
>+   int i;
> 
>+   /* Allocate memory for the gear */
>    gear = malloc(sizeof *gear);
>    if (gear == NULL)
>       return NULL;
> 
>+   /* Calculate the radii used in the gear */
>    r0 = inner_radius;
>    r1 = outer_radius - tooth_depth / 2.0;
>    r2 = outer_radius + tooth_depth / 2.0;
> 
>    da = 2.0 * M_PI / teeth / 4.0;
> 
>-   gear->vertices = calloc(teeth * tris_per_tooth * 3 * 6,
>-			   sizeof *gear->vertices);
>-   s[4] = 0;
>-   c[4] = 1;
>+   /* Allocate memory for the triangle strip information */
>+   gear->nstrips = STRIPS_PER_TOOTH * teeth;
>+   gear->strips = calloc(gear->nstrips, sizeof (*gear->strips));
>+
>+   /* Allocate memory for the vertices */
>+   gear->vertices = calloc(VERTICES_PER_TOOTH * teeth, sizeof(*gear->vertices));
>    v = gear->vertices;
>+
>    for (i = 0; i < teeth; i++) {
>-      s[0] = s[4];
>-      c[0] = c[4];
>+      /* Calculate needed sin/cos for varius angles */
>+      sincos(i * 2.0 * M_PI / teeth, &s[0], &c[0]);
>       sincos(i * 2.0 * M_PI / teeth + da, &s[1], &c[1]);
>       sincos(i * 2.0 * M_PI / teeth + da * 2, &s[2], &c[2]);
>       sincos(i * 2.0 * M_PI / teeth + da * 3, &s[3], &c[3]);
>       sincos(i * 2.0 * M_PI / teeth + da * 4, &s[4], &c[4]);
> 
>-      normal[0] = 0.0;
>-      normal[1] = 0.0;
>-      normal[2] = 1.0;
>-
>-      v = vert(v, r2 * c[1], r2 * s[1], width * 0.5, normal);
>-
>-      v = vert(v, r2 * c[1], r2 * s[1], width * 0.5, normal);
>-      v = vert(v, r2 * c[2], r2 * s[2], width * 0.5, normal);
>-      v = vert(v, r1 * c[0], r1 * s[0], width * 0.5, normal);
>-      v = vert(v, r1 * c[3], r1 * s[3], width * 0.5, normal);
>-      v = vert(v, r0 * c[0], r0 * s[0], width * 0.5, normal);
>-      v = vert(v, r1 * c[4], r1 * s[4], width * 0.5, normal);
>-      v = vert(v, r0 * c[4], r0 * s[4], width * 0.5, normal);
>-
>-      v = vert(v, r0 * c[4], r0 * s[4], width * 0.5, normal);
>-      v = vert(v, r0 * c[0], r0 * s[0], width * 0.5, normal);
>-      v = vert(v, r0 * c[4], r0 * s[4], -width * 0.5, normal);
>-      v = vert(v, r0 * c[0], r0 * s[0], -width * 0.5, normal);
>-
>-      normal[0] = 0.0;
>-      normal[1] = 0.0;
>-      normal[2] = -1.0;
>-
>-      v = vert(v, r0 * c[4], r0 * s[4], -width * 0.5, normal);
>-
>-      v = vert(v, r0 * c[4], r0 * s[4], -width * 0.5, normal);
>-      v = vert(v, r1 * c[4], r1 * s[4], -width * 0.5, normal);
>-      v = vert(v, r0 * c[0], r0 * s[0], -width * 0.5, normal);
>-      v = vert(v, r1 * c[3], r1 * s[3], -width * 0.5, normal);
>-      v = vert(v, r1 * c[0], r1 * s[0], -width * 0.5, normal);
>-      v = vert(v, r2 * c[2], r2 * s[2], -width * 0.5, normal);
>-      v = vert(v, r2 * c[1], r2 * s[1], -width * 0.5, normal);
>-
>-      v = vert(v, r1 * c[0], r1 * s[0], width * 0.5, normal);
>-
>-      v = vert(v, r1 * c[0], r1 * s[0], width * 0.5, normal);
>-      v = vert(v, r1 * c[0], r1 * s[0], -width * 0.5, normal);
>-      v = vert(v, r2 * c[1], r2 * s[1], width * 0.5, normal);
>-      v = vert(v, r2 * c[1], r2 * s[1], -width * 0.5, normal);
>-      v = vert(v, r2 * c[2], r2 * s[2], width * 0.5, normal);
>-      v = vert(v, r2 * c[2], r2 * s[2], -width * 0.5, normal);
>-      v = vert(v, r1 * c[3], r1 * s[3], width * 0.5, normal);
>-      v = vert(v, r1 * c[3], r1 * s[3], -width * 0.5, normal);
>-      v = vert(v, r1 * c[4], r1 * s[4], width * 0.5, normal);
>-      v = vert(v, r1 * c[4], r1 * s[4], -width * 0.5, normal);
>-
>-      v = vert(v, r1 * c[4], r1 * s[4], -width * 0.5, normal);
>+      /* A set of macros for making the creation of the gears easier */
>+#define  GEAR_POINT(r, da) { (r) * c[(da)], (r) * s[(da)] }
>+#define  SET_NORMAL(x, y, z) do { \
>+   normal[0] = (x); normal[1] = (y); normal[2] = (z); \
>+} while(0)
>+
>+#define  GEAR_VERT(v, point, sign) vert((v), p[(point)].x, p[(point)].y, (sign) * width * 0.5, normal)
>+
>+#define START_STRIP do { \
>+   gear->strips[cur_strip].first = v - gear->vertices; \
>+} while(0);
>+
>+#define END_STRIP do { \
>+   int _tmp = (v - gear->vertices); \
>+   gear->strips[cur_strip].count = _tmp - gear->strips[cur_strip].first; \
>+   cur_strip++; \
>+} while (0)
>+
>+#define QUAD_WITH_NORMAL(p1, p2) do { \
>+   SET_NORMAL((p[(p1)].y - p[(p2)].y), -(p[(p1)].x - p[(p2)].x), 0); \
>+   v = GEAR_VERT(v, (p1), -1); \
>+   v = GEAR_VERT(v, (p1), 1); \
>+   v = GEAR_VERT(v, (p2), -1); \
>+   v = GEAR_VERT(v, (p2), 1); \
>+} while(0)
>+
>+      struct point {
>+         GLfloat x;
>+         GLfloat y;
>+      };
>+
>+      /* Create the 7 points (only x,y coords) used to draw a tooth */
>+      struct point p[7] = {
>+         GEAR_POINT(r2, 1), // 0
>+         GEAR_POINT(r2, 2), // 1
>+         GEAR_POINT(r1, 0), // 2
>+         GEAR_POINT(r1, 3), // 3
>+         GEAR_POINT(r0, 0), // 4
>+         GEAR_POINT(r1, 4), // 5
>+         GEAR_POINT(r0, 4), // 6
>+      };
>+
>+      /* Front face */
>+      START_STRIP;
>+      SET_NORMAL(0, 0, 1.0);
>+      v = GEAR_VERT(v, 0, +1);
>+      v = GEAR_VERT(v, 1, +1);
>+      v = GEAR_VERT(v, 2, +1);
>+      v = GEAR_VERT(v, 3, +1);
>+      v = GEAR_VERT(v, 4, +1);
>+      v = GEAR_VERT(v, 5, +1);
>+      v = GEAR_VERT(v, 6, +1);
>+      END_STRIP;
>+
>+      /* Inner face */
>+      START_STRIP;
>+      QUAD_WITH_NORMAL(4, 6);
>+      END_STRIP;
>+
>+      /* Back face */
>+      START_STRIP;
>+      SET_NORMAL(0, 0, -1.0);
>+      v = GEAR_VERT(v, 6, -1);
>+      v = GEAR_VERT(v, 5, -1);
>+      v = GEAR_VERT(v, 4, -1);
>+      v = GEAR_VERT(v, 3, -1);
>+      v = GEAR_VERT(v, 2, -1);
>+      v = GEAR_VERT(v, 1, -1);
>+      v = GEAR_VERT(v, 0, -1);
>+      END_STRIP;
>+
>+      /* Outer face */
>+      START_STRIP;
>+      QUAD_WITH_NORMAL(0, 2);
>+      END_STRIP;
>+
>+      START_STRIP;
>+      QUAD_WITH_NORMAL(1, 0);
>+      END_STRIP;
>+
>+      START_STRIP;
>+      QUAD_WITH_NORMAL(3, 1);
>+      END_STRIP;
>+
>+      START_STRIP;
>+      QUAD_WITH_NORMAL(5, 3);
>+      END_STRIP;
>    }
> 
>-   gear->count = (v - gear->vertices) / 6;
>+   gear->nvertices = (v - gear->vertices);
> 
>+   /* Store the vertices in a vertex buffer object (VBO) */
>    glGenBuffers(1, &gear->vbo);
>    glBindBuffer(GL_ARRAY_BUFFER, gear->vbo);
>-   glBufferData(GL_ARRAY_BUFFER, gear->count * 6 * 4,
>-		gear->vertices, GL_STATIC_DRAW);
>+   glBufferData(GL_ARRAY_BUFFER, gear->nvertices * sizeof(GearVertex),
>+         gear->vertices, GL_STATIC_DRAW);
> 
>    return gear;
> }
> 
>+/** 
>+ * Multiplies two 4x4 matrices.
>+ * 
>+ * The result is stored in matrix m.
>+ * 
>+ * @param m the first matrix to multiply
>+ * @param n the second matrix to multiply
>+ */
> static void
> multiply(GLfloat *m, const GLfloat *n)
> {
>@@ -189,11 +298,20 @@
>       row = n + d.quot * 4;
>       column = m + d.rem;
>       for (j = 0; j < 4; j++)
>-	 tmp[i] += row[j] * column[j * 4];
>+         tmp[i] += row[j] * column[j * 4];
>    }
>    memcpy(m, &tmp, sizeof tmp);
> }
> 
>+/** 
>+ * Rotates a 4x4 matrix.
>+ * 
>+ * @param[in,out] m the matrix to rotate
>+ * @param angle the angle to rotate
>+ * @param x the x component of the direction to rotate to
>+ * @param y the y component of the direction to rotate to
>+ * @param z the z component of the direction to rotate to
>+ */
> static void
> rotate(GLfloat *m, GLfloat angle, GLfloat x, GLfloat y, GLfloat z)
> {
>@@ -210,6 +328,15 @@
>    multiply(m, r);
> }
> 
>+
>+/** 
>+ * Translates a 4x4 matrix.
>+ * 
>+ * @param[in,out] m the matrix to translate
>+ * @param x the x component of the direction to translate to
>+ * @param y the y component of the direction to translate to
>+ * @param z the z component of the direction to translate to
>+ */
> static void
> translate(GLfloat *m, GLfloat x, GLfloat y, GLfloat z)
> {
>@@ -218,98 +345,240 @@
>    multiply(m, t);
> }
> 
>-static const GLfloat light[3] = { 1.0, 1.0, -1.0 };
>-	
>+/** 
>+ * Creates an identity 4x4 matrix.
>+ * 
>+ * @param m the matrix make an identity matrix
>+ */
>+static void
>+identity(GLfloat *m)
>+{
>+   GLfloat t[16] = {
>+      1.0, 0.0, 0.0, 0.0,
>+      0.0, 1.0, 0.0, 0.0,
>+      0.0, 0.0, 1.0, 0.0,
>+      0.0, 0.0, 0.0, 1.0,
>+   };
>+
>+   memcpy(m, t, sizeof(t));
>+}
>+
>+/** 
>+ * Transposes a 4x4 matrix.
>+ *
>+ * @param m the matrix to transpose
>+ */
>+static void 
>+transpose(GLfloat *m)
>+{
>+   GLfloat t[16] = {
>+      m[0], m[4], m[8],  m[12],
>+      m[1], m[5], m[9],  m[13],
>+      m[2], m[6], m[10], m[14],
>+      m[3], m[7], m[11], m[15]};
>+
>+   memcpy(m, t, sizeof(t));
>+}
>+
>+/**
>+ * Inverts a 4x4 matrix.
>+ *
>+ * This function can currently handle only pure translation-rotation matrices.
>+ * Read http://www.gamedev.net/community/forums/topic.asp?topic_id=425118
>+ * for an explanation.
>+ */
> static void
>-draw_gear(struct gear *gear, GLfloat *m,
>-	  GLfloat x, GLfloat y, GLfloat angle, const GLfloat *color)
>+invert(GLfloat *m)
>+{
>+   GLfloat t[16];
>+   identity(t);
>+
>+   // Extract and invert the translation part 't'. The inverse of a
>+   // translation matrix can be calculated by negating the translation
>+   // coordinates.
>+   t[12] = -m[12]; t[13] = -m[13]; t[14] = -m[14];
>+
>+   // Invert the rotation part 'r'. The inverse of a rotation matrix is
>+   // equal to its transpose.
>+   m[12] = m[13] = m[14] = 0;
>+   transpose(m);
>+
>+   // inv(m) = inv(r) * inv(t)
>+   multiply(m, t);
>+}
>+
>+/** 
>+ * Calculate a perspective projection transformation.
>+ * 
>+ * @param m the matrix to save the transformation in
>+ * @param fovy the field of view in the y direction
>+ * @param aspect the view aspect ratio
>+ * @param zNear the near clipping plane
>+ * @param zFar the far clipping plane
>+ */
>+void perspective(GLfloat *m, GLfloat fovy, GLfloat aspect, GLfloat zNear, GLfloat zFar)
> {
>    GLfloat tmp[16];
>+   identity(tmp);
>+
>+   double sine, cosine, cotangent, deltaZ;
>+   GLfloat radians = fovy / 2 * M_PI / 180;
>+
>+   deltaZ = zFar - zNear;
>+   sincos(radians, &sine, &cosine);
>+
>+   if ((deltaZ == 0) || (sine == 0) || (aspect == 0))
>+      return;
> 
>-   memcpy(tmp, m, sizeof tmp);
>-   translate(tmp, x, y, 0);
>-   rotate(tmp, 2 * M_PI * angle / 360.0, 0, 0, 1);
>-   glUniformMatrix4fv(proj_location, 1, GL_FALSE, tmp);
>-   glUniform3fv(light_location, 1, light);
>-   glUniform4fv(color_location, 1, color);
>+   cotangent = cosine / sine;
> 
>+   tmp[0] = cotangent / aspect;
>+   tmp[5] = cotangent;
>+   tmp[10] = -(zFar + zNear) / deltaZ;
>+   tmp[11] = -1;
>+   tmp[14] = -2 * zNear * zFar / deltaZ;
>+   tmp[15] = 0;
>+
>+   memcpy(m, tmp, sizeof(tmp));
>+}
>+
>+/**
>+ * Draws a gear.
>+ *
>+ * @param gear the gear to draw
>+ * @param transform the current transformation matrix
>+ * @param x the x position to draw the gear at
>+ * @param y the y position to draw the gear at
>+ * @param angle the rotation angle of the gear
>+ * @param color the color of the gear
>+ */
>+static void
>+draw_gear(struct gear *gear, GLfloat *transform,
>+      GLfloat x, GLfloat y, GLfloat angle, const GLfloat color[4])
>+{
>+   GLfloat model_view[16];
>+   GLfloat normal_matrix[16];
>+   GLfloat model_view_projection[16];
>+
>+   /* Translate and rotate the gear */
>+   memcpy(model_view, transform, sizeof (model_view));
>+   translate(model_view, x, y, 0);
>+   rotate(model_view, 2 * M_PI * angle / 360.0, 0, 0, 1);
>+
>+   /* Create and set the ModelViewProjectionMatrix */
>+   memcpy(model_view_projection, ProjectionMatrix, sizeof(model_view_projection));
>+   multiply(model_view_projection, model_view);
>+
>+   glUniformMatrix4fv(ModelViewProjectionMatrix_location, 1, GL_FALSE,
>+                      model_view_projection);
>+
>+   /* 
>+    * Create and set the NormalMatrix. It's the inverse transpose of the
>+    * ModelView matrix.
>+    */
>+   memcpy(normal_matrix, model_view, sizeof (normal_matrix));
>+   invert(normal_matrix);
>+   transpose(normal_matrix);
>+   glUniformMatrix4fv(NormalMatrix_location, 1, GL_FALSE, normal_matrix);
>+
>+   /* Set the gear color */
>+   glUniform4fv(MaterialColor_location, 1, color);
>+
>+   /* Set the vertex buffer object to use */
>    glBindBuffer(GL_ARRAY_BUFFER, gear->vbo);
> 
>+   /* Set up the position of the attributes in the vertex buffer object */
>    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE,
>-			 6 * sizeof(GLfloat), NULL);
>+         6 * sizeof(GLfloat), NULL);
>    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE,
>-			 6 * sizeof(GLfloat), (GLfloat *) 0 + 3);
>+         6 * sizeof(GLfloat), (GLfloat *) 0 + 3);
>+
>+   /* Enable the attributes */
>    glEnableVertexAttribArray(0);
>    glEnableVertexAttribArray(1);
>-   glDrawArrays(GL_TRIANGLE_STRIP, 0, gear->count);
>+
>+   /* Draw the triangle strips that comprise the gear */
>+   int n;
>+   for (n = 0; n < gear->nstrips; n++)
>+      glDrawArrays(GL_TRIANGLE_STRIP, gear->strips[n].first, gear->strips[n].count);
>+
>+   /* Disable the attributes */
>+   glDisableVertexAttribArray(1);
>+   glDisableVertexAttribArray(0);
> }
> 
>+/** 
>+ * Draws the gears.
>+ */
> static void
> gears_draw(void)
> {
>    const static GLfloat red[4] = { 0.8, 0.1, 0.0, 1.0 };
>    const static GLfloat green[4] = { 0.0, 0.8, 0.2, 1.0 };
>    const static GLfloat blue[4] = { 0.2, 0.2, 1.0, 1.0 };
>-   GLfloat m[16];
>+   GLfloat transform[16];
>+   identity(transform);
> 
>    glClearColor(0.0, 0.0, 0.0, 0.0);
>    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
> 
>-   memcpy(m, proj, sizeof m);
>-   rotate(m, 2 * M_PI * view_rotx / 360.0, 1, 0, 0);
>-   rotate(m, 2 * M_PI * view_roty / 360.0, 0, 1, 0);
>-   rotate(m, 2 * M_PI * view_rotz / 360.0, 0, 0, 1);
>-
>-   draw_gear(gear1, m, -3.0, -2.0, angle, red);
>-   draw_gear(gear2, m, 3.1, -2.0, -2 * angle - 9.0, green);
>-   draw_gear(gear3, m, -3.1, 4.2, -2 * angle - 25.0, blue);
>+   /* Translate and rotate the view */
>+   translate(transform, 0, 0, -20);
>+   rotate(transform, 2 * M_PI * view_rot[0] / 360.0, 1, 0, 0);
>+   rotate(transform, 2 * M_PI * view_rot[1] / 360.0, 0, 1, 0);
>+   rotate(transform, 2 * M_PI * view_rot[2] / 360.0, 0, 0, 1);
>+
>+   /* Draw the gears */
>+   draw_gear(gear1, transform, -3.0, -2.0, angle, red);
>+   draw_gear(gear2, transform, 3.1, -2.0, -2 * angle - 9.0, green);
>+   draw_gear(gear3, transform, -3.1, 4.2, -2 * angle - 25.0, blue);
> }
> 
>-/* new window size or exposure */
>+/** 
>+ * Handles a new window size or exposure.
>+ * 
>+ * @param width the window width
>+ * @param height the window height
>+ */
> static void
> gears_reshape(int width, int height)
> {
>-   GLfloat ar, m[16] = {
>-      1.0, 0.0, 0.0, 0.0,
>-      0.0, 1.0, 0.0, 0.0,
>-      0.0, 0.0, 0.1, 0.0,
>-      0.0, 0.0, 0.0, 1.0,
>-   };
>-      
>-   if (width < height)
>-      ar = width;
>-   else
>-      ar = height;
>-
>-   m[0] = 0.1 * ar / width;
>-   m[5] = 0.1 * ar / height;
>-   memcpy(proj, m, sizeof proj);
>+   /* Update the projection matrix */
>+   perspective(ProjectionMatrix, 60.0, width / (float)height, 1.0, 1024.0);
>+
>+   /* Set the viewport */
>    glViewport(0, 0, (GLint) width, (GLint) height);
> }
> 
>+/** 
>+ * Handles special eglut events.
>+ * 
>+ * @param special the event to handle.
>+ */
> static void
> gears_special(int special)
> {
>    switch (special) {
>-   case EGLUT_KEY_LEFT:
>-      view_roty += 5.0;
>-      break;
>-   case EGLUT_KEY_RIGHT:
>-      view_roty -= 5.0;
>-      break;
>-   case EGLUT_KEY_UP:
>-      view_rotx += 5.0;
>-      break;
>-   case EGLUT_KEY_DOWN:
>-      view_rotx -= 5.0;
>-      break;
>+      case EGLUT_KEY_LEFT:
>+         view_rot[1] += 5.0;
>+         break;
>+      case EGLUT_KEY_RIGHT:
>+         view_rot[1] -= 5.0;
>+         break;
>+      case EGLUT_KEY_UP:
>+         view_rot[0] += 5.0;
>+         break;
>+      case EGLUT_KEY_DOWN:
>+         view_rot[0] -= 5.0;
>+         break;
>    }
> }
> 
> static void
> gears_idle(void)
> {
>-   static double tRot0 = -1.0;
>+   static int frames = 0;
>+   static double tRot0 = -1.0, tRate0 = -1.0;
>    double dt, t = eglutGet(EGLUT_ELAPSED_TIME) / 1000.0;
> 
>    if (tRot0 < 0.0)
>@@ -322,37 +591,56 @@
>    if (angle > 3600.0)
>       angle -= 3600.0;
> 
>-  eglutPostRedisplay();
>+   eglutPostRedisplay();
>+   frames++;
>+
>+   if (tRate0 < 0.0)
>+      tRate0 = t;
>+   if (t - tRate0 >= 5.0) {
>+      GLfloat seconds = t - tRate0;
>+      GLfloat fps = frames / seconds;
>+      printf("%d frames in %3.1f seconds = %6.3f FPS\n", frames, seconds,
>+            fps);
>+      tRate0 = t;
>+      frames = 0;
>+   }
> }
> 
> static const char vertex_shader[] =
>-   "uniform mat4 proj;\n"
>-   "attribute vec4 position;\n"
>-   "attribute vec4 normal;\n"
>-   "varying vec3 rotated_normal;\n"
>-   "varying vec3 rotated_position;\n"
>-   "vec4 tmp;\n"
>-   "void main()\n"
>-   "{\n"
>-   "   gl_Position = proj * position;\n"
>-   "   rotated_position = gl_Position.xyz;\n"
>-   "   tmp = proj * normal;\n"
>-   "   rotated_normal = tmp.xyz;\n"
>-   "}\n";
>-
>- static const char fragment_shader[] =
>-   //"precision mediump float;\n"
>-   "uniform vec4 color;\n"
>-   "uniform vec3 light;\n"
>-   "varying vec3 rotated_normal;\n"
>-   "varying vec3 rotated_position;\n"
>-   "vec3 light_direction;\n"
>-   "vec4 white = vec4(1.0, 1.0, 1.0, 1.0);\n"
>-   "void main()\n"
>-   "{\n"
>-   "   light_direction = normalize(light - rotated_position);\n"
>-   "   gl_FragColor = color + white * dot(light_direction, rotated_normal);\n"
>-   "}\n";
>+"attribute vec3 position;\n"
>+"attribute vec3 normal;\n"
>+"\n"
>+"uniform mat4 ModelViewProjectionMatrix;\n"
>+"uniform mat4 NormalMatrix;\n"
>+"uniform vec4 LightSourcePosition;\n"
>+"uniform vec4 MaterialColor;\n"
>+"\n"
>+"varying vec4 Color;\n"
>+"\n"
>+"void main(void)\n"
>+"{\n"
>+"    // Transform the normal to eye coordinates\n"
>+"    vec3 N = normalize(vec3(NormalMatrix * vec4(normal, 1.0)));\n"
>+"\n"
>+"    // The LightSourcePosition is actually its direction for directional light\n"
>+"    vec3 L = normalize(LightSourcePosition.xyz);\n"
>+"\n"
>+"    // Multiply the diffuse value by the vertex color (which is fixed in this case)\n"
>+"    // to get the actual color that we will use to draw this vertex with\n"
>+"    float diffuse = max(dot(N, L), 0.0);\n"
>+"    Color = diffuse * MaterialColor;\n"
>+"\n"
>+"    // Transform the position to clip coordinates\n"
>+"    gl_Position = ModelViewProjectionMatrix * vec4(position, 1.0);\n"
>+"}";
>+
>+static const char fragment_shader[] =
>+"varying vec4 Color;\n"
>+"\n"
>+"void main(void)\n"
>+"{\n"
>+"    gl_FragColor = Color;\n"
>+"}";
> 
> static void
> gears_init(void)
>@@ -364,6 +652,7 @@
>    glEnable(GL_CULL_FACE);
>    glEnable(GL_DEPTH_TEST);
> 
>+   /* Compile the vertex shader */
>    p = vertex_shader;
>    v = glCreateShader(GL_VERTEX_SHADER);
>    glShaderSource(v, 1, &p, NULL);
>@@ -371,6 +660,7 @@
>    glGetShaderInfoLog(v, sizeof msg, NULL, msg);
>    printf("vertex shader info: %s\n", msg);
> 
>+   /* Compile the fragment shader */
>    p = fragment_shader;
>    f = glCreateShader(GL_FRAGMENT_SHADER);
>    glShaderSource(f, 1, &p, NULL);
>@@ -378,6 +668,7 @@
>    glGetShaderInfoLog(f, sizeof msg, NULL, msg);
>    printf("fragment shader info: %s\n", msg);
> 
>+   /* Create and link the shader program */
>    program = glCreateProgram();
>    glAttachShader(program, v);
>    glAttachShader(program, f);
>@@ -388,31 +679,41 @@
>    glGetProgramInfoLog(program, sizeof msg, NULL, msg);
>    printf("info: %s\n", msg);
> 
>+   /* Enable the shaders */
>    glUseProgram(program);
>-   proj_location = glGetUniformLocation(program, "proj");
>-   light_location = glGetUniformLocation(program, "light");
>-   color_location = glGetUniformLocation(program, "color");
>+
>+   /* Get the locations of the uniforms so we can access them */
>+   ModelViewProjectionMatrix_location = glGetUniformLocation(program, "ModelViewProjectionMatrix");
>+   NormalMatrix_location = glGetUniformLocation(program, "NormalMatrix");
>+   LightSourcePosition_location = glGetUniformLocation(program, "LightSourcePosition");
>+   MaterialColor_location = glGetUniformLocation(program, "MaterialColor");
>+
>+   /* Set the LightSourcePosition uniform which is constant throught the program */
>+   glUniform4fv(LightSourcePosition_location, 1, LightSourcePosition);
> 
>    /* make the gears */
>-   gear1 = gear(1.0, 4.0, 1.0, 20, 0.7);
>-   gear2 = gear(0.5, 2.0, 2.0, 10, 0.7);
>-   gear3 = gear(1.3, 2.0, 0.5, 10, 0.7);
>+   gear1 = create_gear(1.0, 4.0, 1.0, 20, 0.7);
>+   gear2 = create_gear(0.5, 2.0, 2.0, 10, 0.7);
>+   gear3 = create_gear(1.3, 2.0, 0.5, 10, 0.7);
> }
> 
> int
> main(int argc, char *argv[])
> {
>+   /* Initialize the window */
>    eglutInitWindowSize(300, 300);
>    eglutInitAPIMask(EGLUT_OPENGL_ES2_BIT);
>    eglutInit(argc, argv);
> 
>    eglutCreateWindow("es2gears");
> 
>+   /* Set up eglut callback functions */
>    eglutIdleFunc(gears_idle);
>    eglutReshapeFunc(gears_reshape);
>    eglutDisplayFunc(gears_draw);
>    eglutSpecialFunc(gears_special);
> 
>+   /* Initialize the gears */
>    gears_init();
> 
>    eglutMainLoop();

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Attachments on bug 28790: 36572 | 36993

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