Update shaders to use material to conditionally lookup sub-texture in the atlas

1 files changed, 14 insertions, 2 deletions

diff --git a/gfx/gl/shaders/basicShader.fs b/gfx/gl/shaders/basicShader.fs
index 8bb6350..ab5e58b 100644
--- a/gfx/gl/shaders/basicShader.fs
+++ b/gfx/gl/shaders/basicShader.fs
@@ -1,14 +1,26 @@
 #version 330 core
+#extension GL_ARB_shading_language_420pack : enable
 
 include(`materialInterface.glsl')
 include(`geometryOut.glsl')
 
-uniform sampler2D texture0;
+layout(binding = 0) uniform sampler2D texture0;
+layout(binding = 1) uniform usampler2DRect material;
+
+vec4 getTextureColour(uint midx, vec2 uv)
+{
+	if (midx > 0u) {
+		const vec2 tSize = textureSize(texture0, 0);
+		const vec4 sPosSize = texture(material, uvec2(0, midx - 1u));
+		uv = (sPosSize.xy + sPosSize.zw * fract(uv)) / tSize;
+	}
+	return texture(texture0, uv);
+}
 
 void
 main()
 {
-	vec4 textureColour = texture(texture0, TexCoords);
+	vec4 textureColour = getTextureColour(Material, TexCoords);
 	float clear = round(mix(textureColour.a, 1, Colour.a));
 	gPosition = vec4(FragPos, clear);
 	gNormal = vec4(Normal, clear);