Attachment 75914 Details for Bug 61635 – Test case to show the problem with unnormalized attribute pointers of type GL_UNSIGNED_BYTE

Test case to show the problem with unnormalized attribute pointers of type GL_UNSIGNED_BYTE

glbyte.c (text/plain), 2.05 KB, created by rodrigo on 2013-03-04 19:54:59 UTC

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Creator: rodrigo

Created: 2013-03-04 19:54:59 UTC

Size: 2.05 KB

patch

obsolete

>#include <stdio.h>
>#include <stdlib.h>
>#include <GL/glew.h>
>#include <GL/glut.h>
>
>#define countof(x) (sizeof(x) / sizeof(*(x)))
>
>const char *vshader[] =
>{
>    "attribute vec2 aCoord;\n",
>    "void main(void)\n",
>    "{\n",
>    "    gl_Position = vec4(aCoord.x / 128.0 - 1.0, aCoord.y / 128.0 - 1.0, 0.0, 1.0);\n",
>    "}\n",
>};
>const char *fshader[] =
>{
>    "void main(void)\n",
>    "{\n",
>    "    gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);\n",
>    "}\n",
>};
>
>int g_shader;
>
>struct Vertex
>{
>    unsigned char x, y;
>    //Add some dummy bytes to make the stride non-zero.
>    unsigned char dummy[2];
>};
>struct Vertex star[] =
>{
>    {250, 125},
>    {23, 198},
>    {163, 6},
>    {163, 243},
>    {23, 51},
>    {250, 125},
>};
>
>void Init()
>{
>    int i;
>    //Fill the dummy bytes with random data to make obvious if they are read
>    for (i = 0; i < countof(star); ++i)
>    {
>        star[i].dummy[0] = rand() & 0xFF;
>        star[i].dummy[1] = rand() & 0xFF;
>    }
>    glewInit();
>
>    int vsh = glCreateShader(GL_VERTEX_SHADER);
>    glShaderSource(vsh, countof(vshader), vshader, NULL);
>    glCompileShader(vsh);
>
>    int fsh = glCreateShader(GL_FRAGMENT_SHADER);
>    glShaderSource(fsh, countof(fshader), fshader, NULL);
>    glCompileShader(fsh);
>
>    g_shader = glCreateProgram();
>    glAttachShader(g_shader, vsh);
>    glAttachShader(g_shader, fsh);
>    glLinkProgram(g_shader);
>
>    glBindAttribLocation(g_shader, 0, "aCoord");
>}
>
>void OnDisplay(void)
>{
>    glClear(GL_COLOR_BUFFER_BIT);
>
>    glUseProgram(g_shader);
>
>    glEnableVertexAttribArray(0);
>
>    glVertexAttribPointer(0, 2, GL_UNSIGNED_BYTE, GL_FALSE, sizeof(struct Vertex), star);
>    glDrawArrays(GL_LINE_STRIP, 0, countof(star));
>    glDisableVertexAttribArray(0);
>
>    glUseProgram(0);
>
>    GLuint error;
>    while ((error = glGetError()) != 0)
>        printf("GLError 0x%04X\n", error);
>
>    glutSwapBuffers();
>}
>
>int main(int argc, char **argv)
>{
>    glutInit(&argc, argv);
>
>    glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
>    glutCreateWindow("Test");
>    Init();
>    glutDisplayFunc(OnDisplay);
>
>    glutMainLoop();
>    return 0;
>}

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Attachments on bug 61635: 75733 | 75914

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