Function DrawHistogram

Source/Main/engine.cpp:2420–2466

}

static void DrawHistogram() {
    Shaders* shaders = Shaders::Instance();
    Textures* textures = Textures::Instance();
    Graphics* graphics = Graphics::Instance();

    static int shader_id = -1;
    static VBOContainer vbo;
    if (shader_id == -1) {
        shader_id = shaders->returnProgram("histogram_draw");
        CHECK_GL_ERROR();
        std::vector<GLfloat> data;
        data.resize(kHistogramBuckets * 4);
        for (int i = 0, index = 0; i < kHistogramBuckets; ++i) {
            data[index + 0] = (float)i;
            data[index + 1] = 0.0f;
            data[index + 2] = (float)i;
            data[index + 3] = 1.0f;
            index += 4;
        }
        vbo.Fill(kVBOFloat | kVBOStatic, data.size() * sizeof(GLfloat), &data[0]);
        CHECK_GL_ERROR();
    }

    GLState gl_state;
    gl_state.blend = true;
    gl_state.depth_test = false;
    gl_state.depth_write = false;
    gl_state.cull_face = false;
    graphics->setGLState(gl_state);
    shaders->setProgram(shader_id);
    int vert_attrib_id = shaders->returnShaderAttrib("lines", shader_id);
    int uniform_mvp_id = shaders->returnShaderVariable("mvp", shader_id);
    int uniform_buckets_id = shaders->returnShaderVariable("num_buckets", shader_id);
    glm::mat4 proj_mat;
    proj_mat = glm::ortho(0.0f, (float)graphics->viewport_dim[2], 0.0f, (float)graphics->viewport_dim[3]);
    glm::mat4 mvp_mat = proj_mat;
    shaders->SetUniformInt(uniform_buckets_id, kHistogramBuckets);
    shaders->SetUniformMat4(uniform_mvp_id, (const GLfloat*)&mvp_mat);
    textures->bindTexture(histogram_tex);
    graphics->EnableVertexAttribArray(vert_attrib_id);
    vbo.Bind();
    glVertexAttribPointer(vert_attrib_id, 2, GL_FLOAT, false, 2 * sizeof(GLfloat), 0);
    glLineWidth(1);
    graphics->DrawArrays(GL_LINES, 0, kHistogramBuckets * 2);
    graphics->ResetVertexAttribArrays();
    graphics->BindArrayVBO(0);
}

static void DrawQuad(int shader_id) {
    PROFILER_GPU_ZONE(g_profiler_ctx, "Engine.cpp DrawQuad");