4784a929d7
Replace random buildings with one using proper instancing. Also implement more control over rendering of random buildings. see README.scenery for details.
62 lines
2.7 KiB
GLSL
62 lines
2.7 KiB
GLSL
// -*- mode: C; -*-
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// Licence: GPL v2
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// Author: Frederic Bouvier.
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//
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#version 120
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#extension GL_EXT_draw_instanced : enable
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attribute vec3 instancePosition; // (x,y,z)
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attribute vec3 instanceScaleRotate; // (width, depth, height)
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attribute vec3 rotPitchTex0x; // (rotation, pitch height, texture x offset)
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attribute vec3 tex0yTex1xTex1y; // (texture y offset, texture x gain, texture y gain)
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varying vec3 ecNormal;
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varying float alpha;
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void main() {
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// Determine the rotation for the building.
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float sr = sin(6.28 * rotPitchTex0x.x);
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float cr = cos(6.28 * rotPitchTex0x.x);
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// Adjust pitch of roof to the correct height.
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// The top roof vertices are the only ones that have fractional z values (1.5),
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// so we can use this to identify them and scale up any pitched roof vertex to
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// the correct pitch (rotPitchTex0x.y * 2.0 because of the fractional z value),
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// then scale down by the building height (instanceScaleRotate.z) because
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// immediately afterwards we will scale UP the vertex to the correct scale.
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vec3 position = gl_Vertex.xyz;
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position.z = position.z + fract(position.z) * 2.0 * rotPitchTex0x.y / instanceScaleRotate.z - fract(position.z);
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position = position * instanceScaleRotate.xyz;
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// Rotation of the building and movement into position
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position.xy = vec2(dot(position.xy, vec2(cr, sr)), dot(position.xy, vec2(-sr, cr)));
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position = position + instancePosition.xyz;
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gl_Position = gl_ModelViewProjectionMatrix * vec4(position,1.0);
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// Texture coordinates are stored as tex0 and tex1 across two attributes.
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// tex0 contains the bottom leftmost point, and tex1 contains (w,h).
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gl_TexCoord[0].x = sign(gl_MultiTexCoord0.x) * rotPitchTex0x.z + gl_MultiTexCoord0.x * tex0yTex1xTex1y.y;
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gl_TexCoord[0].y = tex0yTex1xTex1y.x + gl_MultiTexCoord0.y * tex0yTex1xTex1y.z;
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// Rotate the normal.
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ecNormal = gl_Normal;
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// The roof pieces have a normal of (+/-0.7, 0.0, 0.7)
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// If the roof is flat, then we need to change it to (0,0,1).
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// First term evaluates for normals without a +z component (all except roof)
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// Second term evaluates for roof normals with a pitch
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// Third term evaluates for flat roofs
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ecNormal = step(0.5, 1.0 - ecNormal.z) * ecNormal +
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step(0.5, ecNormal.z) * clamp(rotPitchTex0x.y, 0.0, 1.0) * ecNormal +
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step(0.5, ecNormal.z) * (1.0 - clamp(rotPitchTex0x.y, 0.0, 1.0)) * vec3(0,0,1);
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// Rotate the normal as per the building.
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ecNormal.xy = vec2(dot(ecNormal.xy, vec2(cr, sr)), dot(ecNormal.xy, vec2(-sr, cr)));
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ecNormal = gl_NormalMatrix * ecNormal;
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gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
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gl_FrontColor = vec4(1.0, 1.0, 1.0, 1.0);
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gl_BackColor = vec4(1.0, 1.0, 1.0, 1.0);
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alpha = 1.0;
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}
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