87e9118965
Previously there was very limited texture variations as a given texture index was used for both the wall and ceiling. Now these can be specified separately, allowing for more variation in both STG defined and random buildings. Requires simgear commit 053bda26a43314a91b01b08cd4617da82f7ab807
70 lines
3.1 KiB
GLSL
70 lines
3.1 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 rotPitchWtex0x; // (rotation, pitch height, texture x offset)
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attribute vec3 wtex0yTex1xTex1y; // (wall texture y offset, wall/roof texture x gain, wall/roof texture y gain)
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attribute vec3 rtex0xRtex0y; // (roof texture y offset, roof 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 * rotPitchWtex0x.x);
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float cr = cos(6.28 * rotPitchWtex0x.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 (rotPitchWtex0x.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 * rotPitchWtex0x.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:
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// - a separate offset for the wall (wtex0x, wtex0y), and roof (rtex0x, rtex0y)
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// - a shared gain value (tex1x, tex1y)
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//
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// The vertex color value selects between them, with glColor.x=1 indicating walls
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// and glColor.y=1 indicating roofs.
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// Finally, the roof texture is on the left of the texture sheet
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vec2 tex0 = vec2(sign(gl_MultiTexCoord0.x) * (gl_Color.x*rotPitchWtex0x.z + gl_Color.y*rtex0xRtex0y.x),
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gl_Color.x*wtex0yTex1xTex1y.x + gl_Color.y*rtex0xRtex0y.y);
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gl_TexCoord[0].x = tex0.x + gl_MultiTexCoord0.x * wtex0yTex1xTex1y.y;
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gl_TexCoord[0].y = tex0.y + gl_MultiTexCoord0.y * wtex0yTex1xTex1y.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(rotPitchWtex0x.y, 0.0, 1.0) * ecNormal +
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step(0.5, ecNormal.z) * (1.0 - clamp(rotPitchWtex0x.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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