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传递属性给OpenGL顶点着色器的行为奇怪

c++openglglslvertex-shadervertex-attributes
3

问题：

情况1：我将一个顶点属性传递给着色器，程序运行5秒钟，然后图形驱动程序停止响应并恢复，但程序没有。

情况2：我将帧速率限制在60，然后做同样的事情。程序运行良好，但是当我尝试在同一运行时传递不同的顶点属性值时，它不会更新几何图形（只有第一个传递的顶点属性有效）。

我正在使用OpenGL 3.1版本和GLSL 140。（我的显卡/驱动程序支持的最高版本）

我尝试过的解决方法：

在互联网上搜索和阅读教程。由于我还不太了解OpenGL，因此我认为问题在于我不知道要搜索什么。

注意：如果我有一些糟糕的OpenGL编码实践，请原谅，因为我还在学习。

代码：

opengl2_vert.glsl

#version 140

in vec4 offset;

void main(void)
{
    // Declare a hard-coded array of positions
    vec4 vertices[3] = vec4[3](vec4( 0.25, -0.25, 0.5, 1.0),
    vec4(-0.25, -0.25, 0.5, 1.0),
    vec4( 0.25, 0.25, 0.5, 1.0));
    // Index into our array using gl_VertexID
    gl_Position = vertices[gl_VertexID] - offset;
}

Game.cpp

#include "Game.h"


void Game::init()
{
    GLuint vertex_shader = getIO().loadShader("opengl2_vert.glsl", ShaderType::VERTEX);
    GLuint fragment_shader = getIO().loadShader("opengl2_frag.glsl", ShaderType::FRAGMENT);

    // Create program, attach shaders to it, and link it
    program = glCreateProgram();
    glAttachShader(program, vertex_shader);
    glAttachShader(program, fragment_shader);
    glLinkProgram(program);

    GLint isLinked = GL_FALSE;
    glGetProgramiv(program, GL_LINK_STATUS, &isLinked);

    // Logging
    GLint maxLength = 255;
    GLint rLength = 0;
    GLchar* err = new char[maxLength];

    // Vertex shader
    glGetShaderInfoLog(vertex_shader, maxLength, &rLength, err);
    DEBUGSTR((char*)err);

    // Fragment shader
    glGetShaderInfoLog(vertex_shader, maxLength, &rLength, err);
    DEBUGSTR((char*)err);

    // Program
    glGetProgramInfoLog(vertex_shader, maxLength, &rLength, err);
    DEBUGSTR((char*)err);

    delete [] err;
    ASSERT(isLinked == GL_TRUE);



    // Delete the shaders as the program has them now
    glDeleteShader(vertex_shader);
    glDeleteShader(fragment_shader);

    glUseProgram(program);

    // VAO
    glGenVertexArrays(1, &vertex_array_object); // Creates a VAO
    glBindVertexArray(vertex_array_object); // Attaches VAO to rendering context

}

void Game::render(double dt)
{

    //DEBUG("FPS %i", static_cast<int>(1/dt));
    static bool seizure = false;
    seizure = !seizure;
    //(seizure)?getScreen().setBackgroundColor(0.333f, 0.003f, 0.082f):getScreen().setBackgroundColor(0.803f, 0.753f, 0.573f);
    static float angle = 0;
    angle += dt;
    //DEBUG("ANGLE %f %f", cos(angle)/2.0f, sin(angle)/2.0f);

    // Use the program object we created earlier for rendering
    GLfloat attrib[] = {cos(angle)/2.0f, sin(angle)/2.0f, 0.0f, 0.0f};

    glVertexAttrib4fv(glGetAttribLocation(program, "offset"), attrib);


    // Draw one point
    glDrawArrays(GL_TRIANGLES, 0, 3);
}

void Game::shutdown()
{
    glDeleteProgram(program);
    glDeleteVertexArrays(1, &vertex_array_object);
}

IO.cpp

#include "IO.h"

GLuint IO::loadShader(const char* fileName, ShaderType shaderType)
{
    std::ifstream f(fileName, std::ifstream::binary);
    ASSERT(fileName);
    f.seekg(0, std::ios::end);   
    int length = (int)f.tellg();           
    f.seekg(0, std::ios::beg); 
    char* buffer = new char[length+1];  
    f.read(buffer, length); 
    buffer[length] = 0;
    f.close();                   

    const GLchar* in = (const GLchar *)buffer;

    GLuint shader;
    switch(shaderType)
    {
    case VERTEX:
        shader = glCreateShader(GL_VERTEX_SHADER);
        break;

    case FRAGMENT:
        shader = glCreateShader(GL_FRAGMENT_SHADER);
        break;
    }

    glShaderSource(shader, 1, &in, NULL);
    glCompileShader(shader);


    // Logging
    GLint maxLength = 255;
    GLint rLength = 0;
    glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &maxLength);

    GLchar* err = new char[maxLength];
    glGetShaderInfoLog(shader, maxLength, &rLength, err);

    DEBUGSTR((char*)err);

    delete [] err;
    delete [] buffer;

    GLint isCompiled = 0;
    glGetShaderiv(shader, GL_COMPILE_STATUS, &isCompiled);
    ASSERT(isCompiled == GL_TRUE);


    return shader;
}

入口点/游戏循环

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR szCmdLine, int iCmdShow)
{
    // Creating dummy window
    HWND hWnd = getDummyWindow();
    HDC hdc = GetDC(hWnd);
    PIXELFORMATDESCRIPTOR pfd = getWindowsPixelFormatStruct();
    int chosenPixelFormat = ChoosePixelFormat( hdc, &pfd );
    ASSERT(chosenPixelFormat != 0);
    int result = SetPixelFormat(hdc, chosenPixelFormat, &pfd );
    ASSERT(result != NULL);

    // Creating rendering context
    HGLRC hglrc = wglCreateContext(hdc);

    wglMakeCurrent(hdc, hglrc);

    // Getting supported OpenGL version
    DEBUG("System OpenGL version: %s", (char*)glGetString(GL_VERSION));
    DEBUG("Windows pixel format: %i", chosenPixelFormat);

    GLint major_version = 1;
    GLint minor_version = 1;
    glGetIntegerv(GL_MAJOR_VERSION, &major_version);
    glGetIntegerv(GL_MINOR_VERSION, &minor_version);


    GLenum err = glewInit();
    ASSERT(GLEW_OK == err);

    // Getting OpenGL pixel format
    int nPixCount = 0;
    // Specify the important attributes we care about
    int pixAttribs[] = {
        WGL_SUPPORT_OPENGL_ARB, 1, // Must support OGL rendering
        WGL_DRAW_TO_WINDOW_ARB, 1, // pf that can run a window
        WGL_RED_BITS_ARB, 8, // At least 8 bits of red
        WGL_GREEN_BITS_ARB, 8, // At least 8 bits of green
        WGL_BLUE_BITS_ARB, 8, // At least 8 bits of blue
        WGL_DEPTH_BITS_ARB, 16, // At least 16 bits of depth
        WGL_ACCELERATION_ARB, WGL_FULL_ACCELERATION_ARB, // Must be HW accelerated
        WGL_PIXEL_TYPE_ARB, WGL_TYPE_RGBA_ARB, // pf should be RGBA type
        WGL_DOUBLE_BUFFER_ARB, GL_TRUE,
        0} ; // Zero termination
    // Ask OpenGL to find the most relevant format matching our attribs
    // Only get one format back.
    wglChoosePixelFormatARB(hdc,
        &pixAttribs[0],
        NULL,
        1,
        &chosenPixelFormat,
        (UINT*)&nPixCount);
    ASSERT(chosenPixelFormat != -1);
    DEBUG("OpenGL pixel format: %i", chosenPixelFormat);

    // Clean up dummies

    wglDeleteContext(hglrc);
    ReleaseDC(hWnd, hdc);
    DestroyWindow(hWnd);

    // Create window
    hWnd = getWindow(hInstance, TEXT("OpenGL Window"), iCmdShow);
    hdc = GetDC(hWnd);
    result = SetPixelFormat(hdc, chosenPixelFormat, &pfd );
    ASSERT(result != NULL);

    // Creating OpenGL rendering context


    GLint attribs[] =
    {
        WGL_CONTEXT_MAJOR_VERSION_ARB, major_version,
        WGL_CONTEXT_MINOR_VERSION_ARB, minor_version,
        WGL_CONTEXT_PROFILE_MASK_ARB, WGL_CONTEXT_CORE_PROFILE_BIT_ARB,
        0
    };
    DEBUG("Using OpenGL version %i.%i", major_version, minor_version);

    hglrc = wglCreateContextAttribsARB(hdc, 0, attribs);
    wglMakeCurrent(hdc, hglrc);

    // Getting rendering dimensions
    RECT rc_dimensions;
    GetClientRect(hWnd, &rc_dimensions);
    glViewport(0, 0, rc_dimensions.left-1, rc_dimensions.bottom-1); // set viewport


    // Setting up game
    Game game;
    game.getScreen().setWidth(rc_dimensions.left-1);
    game.getScreen().setHeight(rc_dimensions.bottom-1);
    game.getScreen().setFrameCap(59.0f);



    game.init();
    game._getGameTimer().elapsed_time();

    // Starting game loop
    MSG msg;
    float accum_time = 0.0f;
    while(true)
    {
        if(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
        {
            if(msg.message == WM_QUIT)
                break;

            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
        accum_time += game._getGameTimer().elapsed_time();
        if(accum_time > game.getScreen()._getSPF())
        {
            game.render(game.getScreen()._getSPF());

            // Post render
            SwapBuffers(hdc);
            game.getScreen().clearBuffer();

            accum_time -= game.getScreen()._getSPF();
        }
    }

    // Cleaning up before shutdown
    game.shutdown();
    wglDeleteContext(hglrc);
    ReleaseDC(hWnd, hdc);
    DestroyWindow(hWnd);
    UnregisterClass(TEXT("OPENGL"), hInstance);

    return 0;
}

OpenGL支持

Renderer: Intel(R) HD Graphics 3000
Vendor: Intel
Memory: 2108 MB
Version: 3.1.0 - Build 9.17.10.3347
Shading language version: 1.40 - Intel Build 9.17.10.3347


Max texture size: 8192 x 8192
Max vertex texture image units: 16
Max texture image units: 16
Max geometry texture units: 0
Max anisotropic filtering value: 16
Max viewport size: 8192 x 8192
Max Clip Distances: 6
Max samples: 4


Extensions: 129

GL_3DFX_texture_compression_FXT1
GL_ARB_color_buffer_float
GL_ARB_compatibility
GL_ARB_copy_buffer
GL_ARB_depth_buffer_float
GL_ARB_depth_clamp
GL_ARB_depth_texture
GL_ARB_draw_buffers
GL_ARB_draw_buffers_blend
GL_ARB_draw_elements_base_vertex
GL_ARB_draw_instanced
GL_ARB_explicit_attrib_location
GL_ARB_fragment_coord_conventions
GL_ARB_fragment_program
GL_ARB_fragment_program_shadow
GL_ARB_fragment_shader
GL_ARB_framebuffer_object
GL_ARB_framebuffer_sRGB
GL_ARB_half_float_pixel
GL_ARB_half_float_vertex
GL_ARB_instanced_arrays
GL_ARB_map_buffer_range
GL_ARB_multisample
GL_ARB_multitexture
GL_ARB_occlusion_query
GL_ARB_occlusion_query2
GL_ARB_pixel_buffer_object
GL_ARB_point_parameters
GL_ARB_point_sprite
GL_ARB_provoking_vertex
GL_ARB_sampler_objects
GL_ARB_seamless_cube_map
GL_ARB_shader_bit_encoding
GL_ARB_shader_objects
GL_ARB_shading_language_100
GL_ARB_shadow
GL_ARB_sync
GL_ARB_texture_border_clamp
GL_ARB_texture_buffer_object_rgb32
GL_ARB_texture_compression
GL_ARB_texture_compression_rgtc
GL_ARB_texture_cube_map
GL_ARB_texture_env_add
GL_ARB_texture_env_combine
GL_ARB_texture_env_crossbar
GL_ARB_texture_env_dot3
GL_ARB_texture_float
GL_ARB_texture_non_power_of_two
GL_ARB_texture_query_lod
GL_ARB_texture_rectangle
GL_ARB_texture_rg
GL_ARB_texture_rgb10_a2ui
GL_ARB_timer_query
GL_ARB_transpose_matrix
GL_ARB_uniform_buffer_object
GL_ARB_vertex_array_bgra
GL_ARB_vertex_array_object
GL_ARB_vertex_buffer_object
GL_ARB_vertex_program
GL_ARB_vertex_shader
GL_ARB_vertex_type_2_10_10_10_rev
GL_ARB_window_pos
GL_ATI_separate_stencil
GL_EXT_abgr
GL_EXT_bgra
GL_EXT_blend_color
GL_EXT_blend_equation_separate
GL_EXT_blend_func_separate
GL_EXT_blend_minmax
GL_EXT_blend_subtract
GL_EXT_clip_volume_hint
GL_EXT_compiled_vertex_array
GL_EXT_draw_buffers2
GL_EXT_draw_range_elements
GL_EXT_fog_coord
GL_EXT_framebuffer_blit
GL_EXT_framebuffer_multisample
GL_EXT_framebuffer_object
GL_EXT_gpu_program_parameters
GL_EXT_multi_draw_arrays
GL_EXT_packed_depth_stencil
GL_EXT_packed_float
GL_EXT_packed_pixels
GL_EXT_rescale_normal
GL_EXT_secondary_color
GL_EXT_separate_specular_color
GL_EXT_shadow_funcs
GL_EXT_stencil_two_side
GL_EXT_stencil_wrap
GL_EXT_texture3D
GL_EXT_texture_array
GL_EXT_texture_compression_s3tc
GL_EXT_texture_edge_clamp
GL_EXT_texture_env_add
GL_EXT_texture_env_combine
GL_EXT_texture_filter_anisotropic
GL_EXT_texture_integer
GL_EXT_texture_lod_bias
GL_EXT_texture_rectangle
GL_EXT_texture_shared_exponent
GL_EXT_texture_snorm
GL_EXT_texture_sRGB
GL_EXT_texture_swizzle
GL_EXT_transform_feedback
GL_IBM_texture_mirrored_repeat
GL_INTEL_map_texture
GL_INTEL_performance_queries
GL_NV_blend_square
GL_NV_conditional_render
GL_NV_primitive_restart
GL_NV_texgen_reflection
GL_SGIS_generate_mipmap
GL_SGIS_texture_edge_clamp
GL_SGIS_texture_lod
GL_WIN_swap_hint
WGL_ARB_buffer_region
WGL_ARB_create_context
WGL_ARB_extensions_string
WGL_ARB_framebuffer_sRGB
WGL_ARB_make_current_read
WGL_ARB_multisample
WGL_ARB_pbuffer
WGL_ARB_pixel_format
WGL_ARB_pixel_format_float
WGL_EXT_depth_float
WGL_EXT_extensions_string
WGL_EXT_pixel_format_packed_float
WGL_EXT_swap_control
WGL_EXT_swap_control_tear

Core features
v3.0 (100 % - 23/23)
v3.1 (100 % - 8/8)
v3.2 (70 % - 7/10)
v3.3 (70 % - 7/10)
v4.0 (21 % - 3/14)
v4.1 (0 % - 0/7)
v4.2 (0 % - 0/12)
v4.3 (0 % - 0/18)
v4.4 (0 % - 0/10)

OpenGL driver version check (Current: 3.1.0 - Build 9.17.10.3347, Latest known: 9.17.10.3347):
Outdated version of display drivers detected
According the database, you are might be not using the latest version of display drivers for your video card.

No ICD registry entry
The current OpenGL driver doesn't expose the SOFTWARE/Microsoft/Windows (NT)/CurrentVersion/OpenGLDrivers registry entry. Unable to detect the driver version, driver revision name and filename.

Extension verification: 
GL_EXT_color_subtable was not found, but has the entry point glColorSubTableEXT 
GL_EXT_paletted_texture was not found, but has the entry point glColorTableEXT 
GL_EXT_paletted_texture was not found, but has the entry point glGetColorTableEXT 
GL_EXT_paletted_texture was not found, but has the entry point glGetColorTableParameterfvEXT 
GL_EXT_paletted_texture was not found, but has the entry point glGetColorTableParameterivEXT
根据Andon的建议进行了编辑。日志输出中未发现错误。仍然存在同样的问题，只是内存泄漏减少了=P。 - user2940623
我建议你避免在每次绘制时获取属性位置。这个函数需要你使用字符串进行名称搜索（这使它比大多数 glGet... 函数更加昂贵），而且位置直到重新链接程序之前都不会改变。你应该养成在链接程序后查询这些位置并将它们存储在某个地方以避免这种情况的习惯。 - Andon M. Coleman
此外，我不知道 game.getScreen()._getSPF()是如何实现的，但它看起来可能会返回一个常量值... 如果它像 2 * pi 或足够接近 0.0 这样的愚蠢值，则你将有效地向偏移量传递相同的值。 - Andon M. Coleman
_getSPF（）返回每帧秒数1.0f / 60.0f。我也会更改glGet设置。再次感谢！ - user2940623
1
好的！我搞定了！全靠Coleman先生。谢谢。一旦我在链接程序之前添加了glBindAttribLocation并保存了绑定位置，它就像应该旋转一样。=D - user2940623
1
glBindAttribLocation似乎只喜欢1到15之间的数字 >.> 如果我给它0，它只会每3秒更新一次。 - user2940623
1个回答
6
有一些问题需要解决，但我不确定它们是否能解决你的问题。不能保证 in vec4 offset 能被分配到顶点属性位置0。你应该使用glBindAttribLocation (...)将其位置（在链接之前）绑定到0，或者通过名称使用glGetAttribLocation (...)查询位置（在链接之后），而不是盲目地使用魔法数字0。只有在程序执行时实际使用的顶点属性（就像uniforms一样）才会分配属性位置，并且仅分配到顶点属性。因此，您不能假设属性从0开始并按顺序分配，您实际上需要告诉GL要分配什么位置，或者在链接后查询它。
但现在事情变得非常有趣了... #version 140 core。在OpenGL 3.2（GLSL 1.50）之前，单词core实际上没有任何意义。我很惊讶你的GLSL编译器没有抱怨这个。实际上，在GLSL 1.40规范中定义的#version指令仅限于数字，没有其他内容，在1.50中添加了一个可选的配置文件名称。即使着色器成功编译，您也应该检查着色器信息日志，因为它们可能包含警告。
此外，在谈论信息日志时...链接器也会产生一个。您正在编译着色器时检查编译状态，但是没有检查链接状态的代码。
更新：
我注意到你使用的代码查询了你的着色器信息日志，有一些问题：

  1. 假设DEBUGSTR (...)不会删除传递给它的指针，当您的着色器无法编译时，将会泄漏内存。

  2. 如果编译器生成的着色器信息日志>= 255个字符，则会超出你分配的内存。

    • 将这个：GLchar* err = new char[255];改写成这个：GLchar* err = new char[maxLength];。
非常有帮助。我会更改这些内容，看看能找到什么！ - user2940623
谢谢！仍然遇到同样的问题，但代码现在更好了。 - user2940623
谢谢，这帮助我解决了我的顶点着色器中的“0”错误。我在glVertexAttrib4fv中使用了1而不是0，它起作用了。这个问题出现在OpenGL超级宝典第6版列表3.2中。 - GreenOnBlack
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