Method setupProjectiveTexture

OpenCSG/src/channelManager.cpp:356–435

    void ChannelManager::setupProjectiveTexture(ProjTextureSetup setup, GLint texSizeInv)
    {
        mOffscreenBuffer->Bind();
        mOffscreenBuffer->EnableTextureTarget();

        if (setup == FixedFunction)
        {
            static const float splane[4] = { 1.0f, 0.0f, 0.0f, 0.0f };
            static const float tplane[4] = { 0.0f, 1.0f, 0.0f, 0.0f };
            static const float rplane[4] = { 0.0f, 0.0f, 1.0f, 0.0f };
            static const float qplane[4] = { 0.0f, 0.0f, 0.0f, 1.0f };

            glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
            glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
            glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
            glTexGeni(GL_Q, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
            glTexGenfv(GL_S, GL_EYE_PLANE, splane);
            glTexGenfv(GL_T, GL_EYE_PLANE, tplane);
            glTexGenfv(GL_R, GL_EYE_PLANE, rplane);
            glTexGenfv(GL_Q, GL_EYE_PLANE, qplane);
            glEnable(GL_TEXTURE_GEN_S);
            glEnable(GL_TEXTURE_GEN_T);
            glEnable(GL_TEXTURE_GEN_R);
            glEnable(GL_TEXTURE_GEN_Q);
        }

        if (setup == FixedFunction || setup == ARBShader)
        {
            glMatrixMode(GL_TEXTURE);

            const int dx = OpenGL::canvasPos[2] - OpenGL::canvasPos[0];
            const int dy = OpenGL::canvasPos[3] - OpenGL::canvasPos[1];

            // with ARB_texture_rectangle texture coordinates range between
            // 0 and dx resp. dy
            float factorX = static_cast<float>(dx);
            float factorY = static_cast<float>(dy);

            // Otherwise, if the texture rectangle extension is not used:
            // Do not check for the non-power-of-two extension, but simply for
            // the texture format. This seems safer, since it should work always.
            if (!isRectangularTexture()) {
                // with ordinary pow-of-two texture coordinates are between 0 and 1
                // but we must assure only the used part of the texture is taken.
                factorX /= static_cast<float>(mOffscreenBuffer->GetWidth());
                factorY /= static_cast<float>(mOffscreenBuffer->GetHeight());
            }

            float   texCorrect[16] = { factorX, 0.0f, 0.0f, 0.0f,
                                       0.0f, factorY, 0.0f, 0.0f,
                                       0.0f,    0.0f, 1.0f, 0.0f,
                                       0.0f,    0.0f, 0.0f, 1.0f };

            static const float p2ndc[16] = { 0.5f, 0.0f, 0.0f, 0.0f,
                                             0.0f, 0.5f, 0.0f, 0.0f,
                                             0.0f, 0.0f, 0.5f, 0.0f,
                                             0.5f, 0.5f, 0.5f, 1.0f };
            glPushMatrix();