From 6ed208747005774f3fbc90256b9da0c6890a0814 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Thu, 27 Apr 2023 18:36:45 +0100
Subject: Lookup material details once in the vertex shader

... instead of per texel in the fragment shader
---
 gfx/gl/shaders/commonPoint.glsl       | 17 ++++++++++++++++-
 gfx/gl/shaders/dynamicPoint.vs        |  1 +
 gfx/gl/shaders/dynamicPointInst.vs    |  1 +
 gfx/gl/shaders/fixedPoint.vs          |  1 +
 gfx/gl/shaders/material.fs            | 15 +++++----------
 gfx/gl/shaders/materialInterface.glsl |  8 +++++++-
 6 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/gfx/gl/shaders/commonPoint.glsl b/gfx/gl/shaders/commonPoint.glsl
index ecf5fc9..35510e1 100644
--- a/gfx/gl/shaders/commonPoint.glsl
+++ b/gfx/gl/shaders/commonPoint.glsl
@@ -1,3 +1,18 @@
+layout(binding = 1) uniform usampler2DRect materialData;
+
+MaterialDetail
+getMaterialDetail(uint midx)
+{
+	if (midx > 0u) {
+		const vec4 sPosSize = texture(materialData, uvec2(0, midx - 1u));
+		const uvec4 sMode = texture(materialData, uvec2(1, midx - 1u));
+		const uint mapmodeU = sMode.x & 0xFu;
+		const uint mapmodeV = (sMode.x & 0xF0u) >> 1;
+		return MaterialDetail(sPosSize.xy, sPosSize.zw, uvec2(mapmodeU, mapmodeV));
+	}
+	return MaterialDetail(vec2(0, 0), vec2(0, 0), uvec2(0, 0));
+}
+
 void
 main()
 {
@@ -7,7 +22,7 @@ main()
 	TexCoords = texCoord;
 	Normal = (model * vec4(normal, 0.0)).xyz;
 	Colour = colour;
-	Material = material;
+	Material = getMaterialDetail(material);
 
 	gl_Position = viewProjection * worldPos;
 }
diff --git a/gfx/gl/shaders/dynamicPoint.vs b/gfx/gl/shaders/dynamicPoint.vs
index ffa8275..961535c 100644
--- a/gfx/gl/shaders/dynamicPoint.vs
+++ b/gfx/gl/shaders/dynamicPoint.vs
@@ -1,4 +1,5 @@
 #version 330 core
+#extension GL_ARB_shading_language_420pack : enable
 
 include(`meshIn.glsl')
 include(`materialInterface.glsl')
diff --git a/gfx/gl/shaders/dynamicPointInst.vs b/gfx/gl/shaders/dynamicPointInst.vs
index e4c8526..2d6cee5 100644
--- a/gfx/gl/shaders/dynamicPointInst.vs
+++ b/gfx/gl/shaders/dynamicPointInst.vs
@@ -1,4 +1,5 @@
 #version 330 core
+#extension GL_ARB_shading_language_420pack : enable
 
 include(`meshIn.glsl')
 include(`materialInterface.glsl')
diff --git a/gfx/gl/shaders/fixedPoint.vs b/gfx/gl/shaders/fixedPoint.vs
index 6f517ca..ed78c96 100644
--- a/gfx/gl/shaders/fixedPoint.vs
+++ b/gfx/gl/shaders/fixedPoint.vs
@@ -1,4 +1,5 @@
 #version 330 core
+#extension GL_ARB_shading_language_420pack : enable
 
 include(`meshIn.glsl')
 include(`materialInterface.glsl')
diff --git a/gfx/gl/shaders/material.fs b/gfx/gl/shaders/material.fs
index cafb35d..20fa8ab 100644
--- a/gfx/gl/shaders/material.fs
+++ b/gfx/gl/shaders/material.fs
@@ -5,7 +5,6 @@ include(`materialInterface.glsl')
 include(`materialOut.glsl')
 
 layout(binding = 0) uniform sampler2D texture0;
-layout(binding = 1) uniform usampler2DRect material;
 
 float map(uint mapmode, float value)
 {
@@ -24,20 +23,16 @@ float map(uint mapmode, float value)
 	return 0;
 }
 
-vec2 map(uint mapmodeU, uint mapmodeV, vec2 value)
+vec2 map(uvec2 mapmode, vec2 value)
 {
-	return vec2(map(mapmodeU, value.x), map(mapmodeV, value.y));
+	return vec2(map(mapmode.x, value.x), map(mapmode.y, value.y));
 }
 
-vec4 getTextureColour(uint midx, vec2 uv)
+vec4 getTextureColour(MaterialDetail mat, vec2 uv)
 {
-	if (midx > 0u) {
+	if (mat.textureSize.x > 0) {
 		const vec2 tSize = textureSize(texture0, 0);
-		const vec4 sPosSize = texture(material, uvec2(0, midx - 1u));
-		const uvec4 sMode = texture(material, uvec2(1, midx - 1u));
-		const uint mapmodeU = sMode.x & 0xFu;
-		const uint mapmodeV = (sMode.x & 0xF0u) >> 1;
-		uv = (sPosSize.xy + sPosSize.zw * map(mapmodeU, mapmodeV, uv)) / tSize;
+		uv = (mat.textureOrigin + mat.textureSize * map(mat.mapmode, uv)) / tSize;
 	}
 	return texture(texture0, uv);
 }
diff --git a/gfx/gl/shaders/materialInterface.glsl b/gfx/gl/shaders/materialInterface.glsl
index 5735cf9..3a4796b 100644
--- a/gfx/gl/shaders/materialInterface.glsl
+++ b/gfx/gl/shaders/materialInterface.glsl
@@ -1,7 +1,13 @@
+struct MaterialDetail {
+	vec2 textureOrigin;
+	vec2 textureSize;
+	uvec2 mapmode;
+};
+
 ifelse(TYPE, .fs, in, out) vec3 FragPos;
 ifelse(TYPE, .fs, in, out) vec2 TexCoords;
 ifelse(TYPE, .fs, in, out) vec3 Normal;
 ifelse(TYPE, .fs, in, out) vec4 Colour;
 flat
 ifelse(TYPE, .fs, in, out)
-uint Material;
+MaterialDetail Material;
-- 
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