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基本上，我在基于 q3 的游戏中实现了 gamma 校正，以摆脱烦人的SetDeviceGammaRamp。

我将 GL_EXT_framebuffer_object 用于后期处理顶点着色器。它工作得很好，只是它在 nvidia gpus 上有一些奇怪的行为：它强制启用 vsync，除非在控制面板中明确禁用它。如果我使用标准控制面板的设置并启用帧缓冲区，则强制垂直同步，但如果我删除帧缓冲区，它会恢复正常行为。

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初始化：（我猜不相关）

// ouned: gamma correction
const char *g_GammaVertexShaderARB = {
    "void main(void)" "\n"
    "{" "\n"
        "gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;" "\n"
        "gl_TexCoord[0] = gl_MultiTexCoord0;"  "\n"
    "}"
};

const char *g_GammaFragmentShaderARB = {
    "uniform sampler2D sceneBuffer;" "\n"
    "uniform float gamma;" "\n"
    "\n"
    "void main(void)" "\n"
    "{" "\n"
        "vec2 uv = gl_TexCoord[0].xy;" "\n"
        "vec3 color = texture2D(sceneBuffer, uv).rgb;" "\n"
        "if (uv.x<0.50)" "\n"
            "gl_FragColor.rgb = pow(color, vec3(1.0 / 1.5));" "\n"
        "else" "\n"
            "gl_FragColor.rgb = color;" "\n"
        "gl_FragColor.a = 1.0;" "\n"
    "}"
};

    tr.m_hVShader = qglCreateShaderObjectARB(GL_VERTEX_SHADER_ARB);
    qglShaderSourceARB(tr.m_hVShader, 1, (const GLcharARB **)&g_GammaVertexShaderARB, NULL);
    qglCompileShaderARB(tr.m_hVShader);

    if (qglGetError() != GL_NO_ERROR) {
        ri.Printf(PRINT_ERROR, "Failed compiling gamma vertrex shader\n");
    }

    tr.m_hFShader = qglCreateShaderObjectARB(GL_FRAGMENT_SHADER_ARB);
    qglShaderSourceARB(tr.m_hFShader, 1, (const GLcharARB **)&g_GammaFragmentShaderARB, NULL);


    qglCompileShaderARB(tr.m_hFShader);

    if (qglGetError() != GL_NO_ERROR) {
        ri.Printf(PRINT_ERROR, "Failed compiling gamma fragment shader\n");
    }

    tr.gammaProgram = qglCreateProgramObjectARB();
    qglAttachObjectARB(tr.gammaProgram, tr.m_hVShader);
    qglAttachObjectARB(tr.gammaProgram, tr.m_hFShader);
    qglLinkProgramARB(tr.gammaProgram);

    if (qglGetError() != GL_NO_ERROR) {
        ri.Printf(PRINT_ERROR, "Failed linking shaders\n");
    }

    qglUseProgramObjectARB(tr.gammaProgram);

    tr.gammaUniformLoc = qglGetUniformLocationARB(tr.gammaProgram, "gamma");
    tr.gammaSceneBufferLoc = qglGetUniformLocationARB(tr.gammaProgram, "sceneBuffer");

    qglValidateProgramARB(tr.gammaProgram);
    qglUseProgramObjectARB(0);

    // framebuffer object
    tr.gammaFramebuffer = 0;
    qglGenFramebuffersEXT(1, &tr.gammaFramebuffer);
    qglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, tr.gammaFramebuffer);

    // depth buffer
    tr.gammaRenderDepthBuffer = 0;
    qglGenRenderbuffersEXT(1, &tr.gammaRenderDepthBuffer);
    qglBindRenderbufferEXT(GL_RENDERBUFFER_EXT, tr.gammaRenderDepthBuffer);
    qglRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, glConfig.vidWidth, glConfig.vidHeight);

    tr.gammaRenderTarget = 0;
    qglGenTextures(1, &tr.gammaRenderTarget);
    qglBindTexture(GL_TEXTURE_2D, tr.gammaRenderTarget);
    qglTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, glConfig.vidWidth, glConfig.vidHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, 0);
    qglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    qglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    qglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    qglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    qglGenerateMipmapEXT(GL_TEXTURE_2D);

    qglBindTexture(GL_TEXTURE_2D, 0);
    qglFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, tr.gammaRenderTarget, 0);
    qglFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, tr.gammaRenderDepthBuffer);

    qglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

在帧的开头：

    qglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, tr.gammaFramebuffer);
    qglBindRenderbufferEXT(GL_RENDERBUFFER_EXT, tr.gammaRenderDepthBuffer);
    qglDrawBuffer(GL_COLOR_ATTACHMENT0_EXT);

在帧的末尾：

    qglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
    qglBindRenderbufferEXT(GL_RENDERBUFFER_EXT, 0);

    if (!backEnd.projection2D) {
        qglViewport(0, 0, glConfig.vidWidth, glConfig.vidHeight);
        qglScissor(0, 0, glConfig.vidWidth, glConfig.vidHeight);
        qglMatrixMode(GL_PROJECTION);
        qglLoadIdentity();
        qglOrtho(0, glConfig.vidWidth, glConfig.vidHeight, 0, 0, 1);
        qglMatrixMode(GL_MODELVIEW);
        qglLoadIdentity();

        GL_State(GLS_DEPTHTEST_DISABLE);
    }

    qglUseProgramObjectARB(tr.gammaProgram);
    qglEnable(GL_TEXTURE_2D);

    qglUniform1iARB(tr.gammaSceneBufferLoc, 0);

    qglColor3f(tr.identityLight, tr.identityLight, tr.identityLight);
    qglActiveTextureARB(GL_TEXTURE0);
    qglBindTexture(GL_TEXTURE_2D, tr.gammaRenderTarget);

    qglBegin(GL_QUADS);
    qglTexCoord2f(0, 1);
    qglVertex2f(0, 0);
    qglTexCoord2f(1, 1);
    qglVertex2f(glConfig.vidWidth, 0);
    qglTexCoord2f(1, 0);
    qglVertex2f(glConfig.vidWidth, glConfig.vidHeight);
    qglTexCoord2f(0, 0);
    qglVertex2f(0, glConfig.vidHeight);
    qglEnd();

    qglUseProgramObjectARB(0);

那么，还有什么可以导致启用 vsync 呢？

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0 回答 0