56 lines
1.9 KiB
GLSL
56 lines
1.9 KiB
GLSL
#version 150
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// This is the terrain fragment shader. There is a lot of code in here
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// which is not necessary to render the terrain, but included for convenience -
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// Like generating normals from the heightmap or a simple fog effect.
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// Most of the time you want to adjust this shader to get your terrain the look
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// you want. The vertex shader most likely will stay the same.
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in vec2 terrain_uv;
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in vec3 vtx_pos;
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out vec4 color;
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uniform struct {
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sampler2D data_texture;
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sampler2D heightfield;
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int view_index;
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int terrain_size;
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int chunk_size;
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} ShaderTerrainMesh;
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uniform sampler2D p3d_Texture0;
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uniform vec3 wspos_camera;
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// Compute normal from the heightmap, this assumes the terrain is facing z-up
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vec3 get_terrain_normal() {
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const float terrain_height = 50.0;
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vec3 pixel_size = vec3(1.0, -1.0, 0) / textureSize(ShaderTerrainMesh.heightfield, 0).xxx;
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float u0 = texture(ShaderTerrainMesh.heightfield, terrain_uv + pixel_size.yz).x * terrain_height;
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float u1 = texture(ShaderTerrainMesh.heightfield, terrain_uv + pixel_size.xz).x * terrain_height;
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float v0 = texture(ShaderTerrainMesh.heightfield, terrain_uv + pixel_size.zy).x * terrain_height;
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float v1 = texture(ShaderTerrainMesh.heightfield, terrain_uv + pixel_size.zx).x * terrain_height;
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vec3 tangent = normalize(vec3(1.0, 0, u1 - u0));
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vec3 binormal = normalize(vec3(0, 1.0, v1 - v0));
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return normalize(cross(tangent, binormal));
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}
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void main() {
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vec3 diffuse = texture(p3d_Texture0, terrain_uv * 16.0).xyz;
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vec3 normal = get_terrain_normal();
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// Add some fake lighting - you usually want to use your own lighting code here
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vec3 fake_sun = normalize(vec3(0.7, 0.2, 0.6));
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vec3 shading = max(0.0, dot(normal, fake_sun)) * diffuse;
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shading += vec3(0.07, 0.07, 0.1);
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// Fake fog
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float dist = distance(vtx_pos, wspos_camera);
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float fog_factor = smoothstep(0, 1, dist / 1000.0);
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shading = mix(shading, vec3(0.7, 0.7, 0.8), fog_factor);
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color = vec4(shading, 1.0);
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}
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