From 0aec63ef08aea4692b2ce5359f898b5be75c6f38 Mon Sep 17 00:00:00 2001
From: LaG1924 <12997935+LaG1924@users.noreply.github.com>
Date: Wed, 1 Nov 2017 20:58:46 +0500
Subject: Minor shader optimization

---
 cwd/shaders/face.vs | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

(limited to 'cwd/shaders/face.vs')

diff --git a/cwd/shaders/face.vs b/cwd/shaders/face.vs
index 2d3b4b5..dbb8dd8 100644
--- a/cwd/shaders/face.vs
+++ b/cwd/shaders/face.vs
@@ -17,13 +17,23 @@ out VS_OUT {
 //uniform  mat4 projection;
 uniform mat4 projView;
 
+vec2 TransformTextureCoord(vec4 TextureAtlasCoords, vec2 UvCoords) {
+    float x = TextureAtlasCoords.x;
+    float y = TextureAtlasCoords.y;
+    float w = TextureAtlasCoords.z;
+    float h = TextureAtlasCoords.w;
+    vec2 A = vec2(x, 1 - y - h);
+    vec2 B = vec2(x + w, 1 - y);
+    return A + UvCoords * (B - A);
+}
+
 void main()
 {
     vec4 sourcePosition = vec4(position,1.0f);
     gl_Position = projView * model * sourcePosition;
 
     vs_out.UvPosition = vec2(UvCoordinates.x,UvCoordinates.y);
-    vs_out.Texture = Texture;
+    vs_out.Texture = TransformTextureCoord(Texture,UvCoordinates);
     vs_out.Color = color;
     vs_out.Light = light;
 }
-- 
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