Real-Time Rendering Pipelines, Forward vs. Deferred Shading, and GLSL

Modern GPU rendering turns 3D polygonal vertex meshes into 2D screen pixels. This guide covers programmable GPU stages (Vertex Shader, Rasterizer, Fragment Shader), Forward Rendering vs. Deferred Shading (G-Buffer), and draw call optimization.

⚡ Quick Dive

Forward Rendering vs. Deferred Shading

Dimension Forward Rendering Deferred Shading
Complexity $O(\text{Geometry} \times \text{Lights})$ $O(\text{Geometry} + \text{Lights})$
Light Scaling Poor (Max ~10-20 dynamic lights per object) ⚡ Massive (Thousands of dynamic lights)
Memory Bandwidth Low (Direct to backbuffer) High (Requires Multiple Render Targets / G-Buffer)
Transparency Simple (Standard alpha blending) Complex (Requires forward pass for transparent meshes)

📖 Extended Guide

1. Minimal Vertex & Fragment Shader (GLSL)

// vertex_shader.glsl
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec2 aTexCoord;

uniform mat4 uMVP;
out vec2 TexCoord;

void main() {
    gl_Position = uMVP * vec4(aPos, 1.0);
    TexCoord = aTexCoord;
}

// fragment_shader.glsl
#version 330 core
out vec4 FragColor;
in vec2 TexCoord;

uniform sampler2D uTexture;

void main() {
    FragColor = texture(uTexture, TexCoord);
}
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