Attachment 121191 Details for Bug 93813 – Test case

Test case

misaligned_viewport_clip_control.cc (text/plain), 4.81 KB, created by James Legg on 2016-01-21 17:58:28 UTC

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Creator: James Legg

Created: 2016-01-21 17:58:28 UTC

Size: 4.81 KB

patch

obsolete

>// Compile with c++ [filepath] -std=c++11 -Wall $(pkg-config --cflags --libs sdl2 gl)
>
>#define GL_GLEXT_PROTOTYPES
>#include <GL/gl.h>
>#include <SDL.h>
>#include <SDL_video.h>
>#include <iostream>
>#include <cassert>
>
>#define GL_ZERO_TO_ONE                    0x935F
>
>const GLchar * const vertex_shader_source =
>R"(
>#version 330 core
>
>void main()
>{
>	gl_Position = vec4(
>		float(gl_VertexID % 2) * 4.0 - 1.0,
>		float(gl_VertexID / 2) * 4.0 - 1.0,
>		0.5,
>		1.0);
>}
>)";
>
>const GLchar * const fragment_shader_source =
>R"(
>#version 330 core
>
>layout(location = 0) out vec4 c;
>
>void main()
>{
>	c = vec4(1.0);
>}
>)";
>
>int main()
>{
>	constexpr const auto textureSizeX = 1u;
>	constexpr const auto textureSizeY = 5u;
>	SDL_Init(SDL_INIT_VIDEO);
>	SDL_Window * const window = SDL_CreateWindow(
>		"Test",
>		SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720,
>		SDL_WINDOW_OPENGL);
>	if (!window)
>	{
>		std::cerr << "Could not create window: "
>		          << SDL_GetError() << '\n';
>		return 1;
>	}
>
>	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
>	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
>	SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG | SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG);
>	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
>	SDL_GLContext gl_context = SDL_GL_CreateContext(window);
>	if (gl_context == NULL)
>	{
>		std::cerr << "Could not create OpenGL 3.3 context: "
>		          << SDL_GetError() << '\n';
>		return 1;
>	}
>
>	// Setting GL_CLIP_ORIGIN to GL_UPPER_LEFT is necessary to reproduce
>	// the bug.
>	typedef void (APIENTRYP PFNGLCLIPCONTROLPROC) (GLenum origin, GLenum depth);
>	const auto glClipControl = reinterpret_cast<PFNGLCLIPCONTROLPROC>(
>		SDL_GL_GetProcAddress("glClipControl"));
>	glClipControl(GL_UPPER_LEFT, GL_ZERO_TO_ONE);
>
>	GLuint texture;
>	glGenTextures(1, &texture);
>	glBindTexture(GL_TEXTURE_2D, texture);
>	glTexStorage2D(GL_TEXTURE_2D, 1, GL_R8, textureSizeX, textureSizeY);
>
>	GLuint framebuffer;
>	glGenFramebuffers(1, &framebuffer);
>	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, framebuffer);
>	glFramebufferTexture(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, texture, 0);
>
>	const GLenum framebuffer_status = glCheckFramebufferStatus(GL_DRAW_FRAMEBUFFER);
>	assert(framebuffer_status == GL_FRAMEBUFFER_COMPLETE);
>
>	glClear(GL_COLOR_BUFFER_BIT);
>
>	const GLuint vertex_shader = glCreateShader(GL_VERTEX_SHADER);
>	glShaderSource(vertex_shader, 1, const_cast<const GLchar**>(&vertex_shader_source), 0);
>	glCompileShader(vertex_shader);
>	{
>		GLint is_compiled;
>		glGetShaderiv(vertex_shader, GL_COMPILE_STATUS, &is_compiled);
>		if (is_compiled == GL_FALSE)
>		{
>			GLint max_length;
>			glGetShaderiv(vertex_shader, GL_INFO_LOG_LENGTH, &max_length);
>
>			char * vertex_info_log = new char[max_length];
>
>			glGetShaderInfoLog(vertex_shader, max_length, &max_length, vertex_info_log);
>
>			std::cerr << "Error compiling vertex shader:\n"
>			          << vertex_info_log;
>			return 1;
>		}
>	}
>
>	const GLuint fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
>	glShaderSource(fragment_shader, 1, const_cast<const GLchar**>(&fragment_shader_source), 0);
>	glCompileShader(fragment_shader);
>	{
>		GLint is_compiled;
>		glGetShaderiv(fragment_shader, GL_COMPILE_STATUS, &is_compiled);
>		if (is_compiled == GL_FALSE)
>		{
>			GLint max_length;
>			glGetShaderiv(fragment_shader, GL_INFO_LOG_LENGTH, &max_length);
>
>			char * fragment_info_log = new char[max_length];
>
>			glGetShaderInfoLog(fragment_shader, max_length, &max_length, fragment_info_log);
>
>			std::cerr << "Error compiling fragment shader:\n"
>			          << fragment_info_log;
>			return 1;
>		}
>	}
>
>	const GLuint shader_program = glCreateProgram();
>	glAttachShader(shader_program, vertex_shader);
>	glAttachShader(shader_program, fragment_shader);
>	glLinkProgram(shader_program);
>	{
>		GLint is_linked;
>		glGetProgramiv(shader_program, GL_LINK_STATUS, &is_linked);
>		if (is_linked == GL_FALSE)
>		{
>			GLint max_length;
>			glGetProgramiv(shader_program, GL_INFO_LOG_LENGTH, &max_length);
>
>			char * program_info_log = new char[max_length];
>
>			glGetProgramInfoLog(shader_program, max_length, &max_length, program_info_log);
>
>			std::cerr << "Error linking shader:\n"
>			          << program_info_log;
>			return 1;
>		}
>	}
>	glUseProgram(shader_program);
>	glViewport(0,1,1,3);
>
>	GLuint vertex_array;
>	glGenVertexArrays(1, &vertex_array);
>	glBindVertexArray(vertex_array);
>	glDrawArrays(GL_TRIANGLE_STRIP, 0, 3);
>	GLfloat colours[textureSizeX * textureSizeY];
>	glGetTexImage(GL_TEXTURE_2D, 0, GL_RED, GL_FLOAT, colours);
>
>	assert(glGetError() == GL_NO_ERROR);
>
>	std::cout << colours[0] << ", " << colours[2] << "\n";
>	// This was outside the viewport, so should be black from the clear
>	assert(colours[0] == 0.0f);
>	// This was inside the viewport, so should be red from the draw
>	assert(colours[2] == 1.0f);
>	// Expected output is "1, 0".
>
>	SDL_GL_DeleteContext(gl_context);
>	SDL_DestroyWindow(window);
>	SDL_Quit();
>}
>

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Attachments on bug 93813: 121191

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