From 4ae26db5ec12560ee2d76a1bdc78b34a45c7442a Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sat, 20 Jul 2024 19:23:58 +0100
Subject: Pull material lookup functions into a common file

---
 gfx/gl/shaders/materialCommon.glsl | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 gfx/gl/shaders/materialCommon.glsl

(limited to 'gfx/gl/shaders/materialCommon.glsl')

diff --git a/gfx/gl/shaders/materialCommon.glsl b/gfx/gl/shaders/materialCommon.glsl
new file mode 100644
index 0000000..a915ce3
--- /dev/null
+++ b/gfx/gl/shaders/materialCommon.glsl
@@ -0,0 +1,35 @@
+layout(binding = 0) uniform sampler2D texture0;
+
+float
+map(uint mapmode, float value)
+{
+	switch (mapmode) {
+		case 0u: // Repeat
+			return fract(value);
+		case 1u: // Clamp to edge
+			return clamp(0.0, 1.0, value);
+		case 2u: // Mirror
+			discard;
+		case 3u: // Decal
+			if (value != clamp(0.0, 1.0, value)) {
+				discard;
+			}
+	}
+	return 0;
+}
+
+vec2
+map(uvec2 mapmode, vec2 value)
+{
+	return vec2(map(mapmode.x, value.x), map(mapmode.y, value.y));
+}
+
+vec4
+getTextureColour(MaterialDetail mat, vec2 uv)
+{
+	if (mat.textureSize.x > 0) {
+		const vec2 tSize = textureSize(texture0, 0);
+		uv = (mat.textureOrigin + mat.textureSize * map(mat.mapmode, uv)) / tSize;
+	}
+	return texture(texture0, uv);
+}
-- 
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