3D Render

  • I am trying to solve the below. I am newbie to game programming. Any pointers would be helpful here.

    Consider the following 3D scene representing an old town's main square:
    • A single statue
    static geometry, high polygon count
    low complexity fragment shader
    • A particle system simulating smoke
    animated, rendered as a large set of points
    • A small set of characters
    animated geometry, medium polygon count
    medium complexity fragment shader
    • A large set of buildings
    static geometry, low polygon count
    low complexity fragment shader
    • A background image/skybox
    • The camera/viewpoint is continuously moving within the scene.

    How would you render the statue - by itself – using OpenGL to achieve maximum vertex performance (vertices/second)?

    How would you render the particle system - by itself - using OpenGL to achieve maximum vertex performance (vertices/second)?

    How would you render the scene - as a whole - most efficiently on a GPU using OpenGL?

    Given that the 3D scene was being rendered correctly but that you wanted to improve the performance further, how would you determine if the main performance limitation/bottleneck was located in the application, in the vertex processing stage, or in the fragment processing stage?

  • Anyone has any suggestions here? I am new to OpenGL programming.
    To render particles, I can use shaders.

    Code is as below. Any comments?
    #version 330 core
    layout (location = 0) in vec4 vertex; // <vec2 position, vec2 texCoords>

    out vec2 TexCoords;
    out vec4 ParticleColor;

    uniform mat4 projection;
    uniform vec2 offset;
    uniform vec4 color;

    void main()
    float scale = 10.0f;
    TexCoords = vertex.zw;
    ParticleColor = color;
    gl_Position = projection * vec4((vertex.xy * scale) + offset, 0.0, 1.0);

    //Below code to render particles
    glBlendFunc(GL_SRC_ALPHA, GL_ONE);
    for (Particle particle : particles)
    if (particle.Life > 0.0f)
    particleShader.SetVector2f("offset", particle.Position);
    particleShader.SetVector4f("color", particle.Color);
    glDrawArrays(GL_TRIANGLES, 0, 6);

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