From 9fe26209b79fbb92b51b5ccff85ee62ffca71991 Mon Sep 17 00:00:00 2001
From: Ray <raysan5@gmail.com>
Date: Wed, 17 Mar 2021 13:59:22 +0100
Subject: REVIEWED: Instancing example to work on web

---
 .../shaders/glsl100/base_lighting_instanced.vs     | 54 ++++++++++++++++------
 1 file changed, 40 insertions(+), 14 deletions(-)

(limited to 'examples/web/shaders/resources')

diff --git a/examples/web/shaders/resources/shaders/glsl100/base_lighting_instanced.vs b/examples/web/shaders/resources/shaders/glsl100/base_lighting_instanced.vs
index 5e5430b..c8e2560 100644
--- a/examples/web/shaders/resources/shaders/glsl100/base_lighting_instanced.vs
+++ b/examples/web/shaders/resources/shaders/glsl100/base_lighting_instanced.vs
@@ -1,36 +1,62 @@
-#version 330
+#version 100
 
 // Input vertex attributes
-in vec3 vertexPosition;
-in vec2 vertexTexCoord;
-in vec3 vertexNormal;
-in vec4 vertexColor;
+attribute vec3 vertexPosition;
+attribute vec2 vertexTexCoord;
+attribute vec3 vertexNormal;
+attribute vec4 vertexColor;
 
-layout (location = 12) in mat4 instance;
+attribute mat4 instance;
 
 // Input uniform values
 uniform mat4 mvp;
 
 // Output vertex attributes (to fragment shader)
-out vec3 fragPosition;
-out vec2 fragTexCoord;
-out vec4 fragColor;
-out vec3 fragNormal;
+varying vec3 fragPosition;
+varying vec2 fragTexCoord;
+varying vec4 fragColor;
+varying vec3 fragNormal;
 
 // NOTE: Add here your custom variables
 
+// https://github.com/glslify/glsl-inverse
+mat3 inverse(mat3 m)
+{
+  float a00 = m[0][0], a01 = m[0][1], a02 = m[0][2];
+  float a10 = m[1][0], a11 = m[1][1], a12 = m[1][2];
+  float a20 = m[2][0], a21 = m[2][1], a22 = m[2][2];
+
+  float b01 = a22*a11 - a12*a21;
+  float b11 = -a22*a10 + a12*a20;
+  float b21 = a21*a10 - a11*a20;
+
+  float det = a00*b01 + a01*b11 + a02*b21;
+
+  return mat3(b01, (-a22*a01 + a02*a21), (a12*a01 - a02*a11),
+              b11, (a22*a00 - a02*a20), (-a12*a00 + a02*a10),
+              b21, (-a21*a00 + a01*a20), (a11*a00 - a01*a10))/det;
+}
+
+// https://github.com/glslify/glsl-transpose
+mat3 transpose(mat3 m)
+{
+  return mat3(m[0][0], m[1][0], m[2][0],
+              m[0][1], m[1][1], m[2][1],
+              m[0][2], m[1][2], m[2][2]);
+}
+
 void main()
 {
     // Send vertex attributes to fragment shader
-    fragPosition = vec3(instance * vec4(vertexPosition, 1.0));
+    fragPosition = vec3(instance*vec4(vertexPosition, 1.0));
     fragTexCoord = vertexTexCoord;
     fragColor = vertexColor;
 
     mat3 normalMatrix = transpose(inverse(mat3(instance)));
-    fragNormal = normalize(normalMatrix * vertexNormal);
+    fragNormal = normalize(normalMatrix*vertexNormal);
 
-    mat4 mvpi = mvp * instance;
+    mat4 mvpi = mvp*instance;
 
     // Calculate final vertex position
-    gl_Position = mvpi * vec4(vertexPosition, 1.0);
+    gl_Position = mvpi*vec4(vertexPosition, 1.0);
 }
-- 
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