riffusion-app/shaders.js

61 lines
1.8 KiB
JavaScript

export const vertexShader = `
// Uniforms are data that are shared between shaders
// The contain data that are uniform across the entire frame.
// The heightmap and scaling constant for each point are uniforms in this respect.
// A uniform to contain the heightmap image
uniform sampler2D bumpTexture;
// A uniform to contain the scaling constant
uniform float bumpScale;
// Varyings are variables whose values are decided in the vertext shader
// But whose values are then needed in the fragment shader
// A variable to store the height of the point
varying float vAmount;
// The UV mapping coordinates of a vertex
varying vec2 vUV;
void main()
{
// The "coordinates" in UV mapping representation
vUV = uv;
// The heightmap data at those coordinates
vec4 bumpData = texture2D(bumpTexture, uv);
// height map is grayscale, so it doesn't matter if you use r, g, or b.
vAmount = bumpData.r;
// move the position along the normal
vec3 newPosition = position + normal * bumpScale * vAmount;
// Compute the position of the vertex using a standard formula
gl_Position = projectionMatrix * modelViewMatrix * vec4(newPosition, 1.0);
}
`;
export const fragmentShader = `
// A uniform for the terrain texture image
uniform sampler2D terrainTexture;
// Get the varyings from the vertex shader
varying vec2 vUV;
// vAmount isn't really used, but could be if necessary
varying float vAmount;
uniform lowp float shadows;
uniform lowp float highlights;
const mediump vec3 luminanceWeighting = vec3(0.3, 0.3, 0.3);
void main()
{
// Get the color of the fragment from the texture map
// at that coordinate in the UV mapping
vec4 source = texture2D(terrainTexture, vUV);
gl_FragColor = vec4(source.r - 0.05, source.g - 0.05, source.b + 0.1, 1.0);
}
`;