From 81b69f17e1c3299aae9e762bd8dfc808449ba78d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Sat, 10 Nov 2012 21:26:00 +0100
Subject: [PATCH] Shaders: another iteration in porting of Phong and Flat
 shaders to GLES.

Hope the reduced precision won't hurt.
---
 src/Shaders/FlatShader2D.frag  |  4 ++--
 src/Shaders/FlatShader2D.vert  |  6 +++---
 src/Shaders/PhongShader.frag   | 28 ++++++++++++++--------------
 src/Shaders/PhongShader.vert   | 24 ++++++++++++------------
 src/Shaders/compatibility.glsl |  7 +++++++
 5 files changed, 38 insertions(+), 31 deletions(-)

diff --git a/src/Shaders/FlatShader2D.frag b/src/Shaders/FlatShader2D.frag
index bdc52dd38..44051058d 100644
--- a/src/Shaders/FlatShader2D.frag
+++ b/src/Shaders/FlatShader2D.frag
@@ -2,10 +2,10 @@
 #define fragmentColor gl_FragColor
 #endif
 
-uniform vec3 color;
+uniform lowp vec3 color;
 
 #ifndef NEW_GLSL
-out vec4 fragmentColor;
+out lowp vec4 fragmentColor;
 #endif
 
 void main() {
diff --git a/src/Shaders/FlatShader2D.vert b/src/Shaders/FlatShader2D.vert
index 60355d131..dc702bf98 100644
--- a/src/Shaders/FlatShader2D.vert
+++ b/src/Shaders/FlatShader2D.vert
@@ -2,12 +2,12 @@
 #define in attribute
 #endif
 
-uniform mat3 transformationProjection;
+uniform highp mat3 transformationProjection;
 
 #ifdef EXPLICIT_ATTRIB_LOCATION
-layout(location = 0) in vec3 position;
+layout(location = 0) in highp vec3 position;
 #else
-in vec3 position;
+in highp vec3 position;
 #endif
 
 void main() {
diff --git a/src/Shaders/PhongShader.frag b/src/Shaders/PhongShader.frag
index 638a1e3fa..aa8125401 100644
--- a/src/Shaders/PhongShader.frag
+++ b/src/Shaders/PhongShader.frag
@@ -3,35 +3,35 @@
 #define color gl_FragColor
 #endif
 
-uniform vec3 ambientColor = vec3(0.0, 0.0, 0.0);
-uniform vec3 diffuseColor;
-uniform vec3 specularColor = vec3(1.0, 1.0, 1.0);
-uniform vec3 lightColor = vec3(1.0, 1.0, 1.0);
-uniform float shininess = 80.0;
+uniform lowp vec3 ambientColor = vec3(0.0, 0.0, 0.0);
+uniform lowp vec3 diffuseColor;
+uniform lowp vec3 specularColor = vec3(1.0, 1.0, 1.0);
+uniform lowp vec3 lightColor = vec3(1.0, 1.0, 1.0);
+uniform mediump float shininess = 80.0;
 
-in vec3 transformedNormal;
-in vec3 lightDirection;
-in vec3 cameraDirection;
+in mediump vec3 transformedNormal;
+in highp vec3 lightDirection;
+in highp vec3 cameraDirection;
 
 #ifdef NEW_GLSL
-out vec4 color;
+out lowp vec4 color;
 #endif
 
 void main() {
     /* Ambient color */
     color.rgb = ambientColor;
 
-    vec3 normalizedTransformedNormal = normalize(transformedNormal);
-    vec3 normalizedLightDirection = normalize(lightDirection);
+    mediump vec3 normalizedTransformedNormal = normalize(transformedNormal);
+    highp vec3 normalizedLightDirection = normalize(lightDirection);
 
     /* Add diffuse color */
-    float intensity = max(0.0, dot(normalizedTransformedNormal, normalizedLightDirection));
+    lowp float intensity = max(0.0, dot(normalizedTransformedNormal, normalizedLightDirection));
     color.rgb += diffuseColor*lightColor*intensity;
 
     /* Add specular color, if needed */
     if(intensity != 0) {
-        vec3 reflection = reflect(-normalizedLightDirection, normalizedTransformedNormal);
-        float specularity = pow(max(0.0, dot(normalize(cameraDirection), reflection)), shininess);
+        highp vec3 reflection = reflect(-normalizedLightDirection, normalizedTransformedNormal);
+        mediump float specularity = pow(max(0.0, dot(normalize(cameraDirection), reflection)), shininess);
         color.rgb += specularColor*specularity;
     }
 
diff --git a/src/Shaders/PhongShader.vert b/src/Shaders/PhongShader.vert
index 1c794cbce..b544d63f8 100644
--- a/src/Shaders/PhongShader.vert
+++ b/src/Shaders/PhongShader.vert
@@ -3,26 +3,26 @@
 #define out varying
 #endif
 
-uniform mat4 transformationMatrix;
-uniform mat4 projectionMatrix;
-uniform vec3 light;
+uniform highp mat4 transformationMatrix;
+uniform highp mat4 projectionMatrix;
+uniform highp vec3 light;
 
 #ifdef EXPLICIT_ATTRIB_LOCATION
-layout(location = 0) in vec4 position;
-layout(location = 1) in vec3 normal;
+layout(location = 0) in highp vec4 position;
+layout(location = 1) in mediump vec3 normal;
 #else
-in vec4 position;
-in vec3 normal;
+in highp vec4 position;
+in mediump vec3 normal;
 #endif
 
-out vec3 transformedNormal;
-out vec3 lightDirection;
-out vec3 cameraDirection;
+out mediump vec3 transformedNormal;
+out highp vec3 lightDirection;
+out highp vec3 cameraDirection;
 
 void main() {
     /* Transformed vertex position */
-    vec4 transformedPosition4 = transformationMatrix*position;
-    vec3 transformedPosition = transformedPosition4.xyz/transformedPosition4.w;
+    highp vec4 transformedPosition4 = transformationMatrix*position;
+    highp vec3 transformedPosition = transformedPosition4.xyz/transformedPosition4.w;
 
     /* Transformed normal vector */
     transformedNormal = normalize(mat3x3(transformationMatrix)*normal);
diff --git a/src/Shaders/compatibility.glsl b/src/Shaders/compatibility.glsl
index 2ccbfae6b..70f4cd6ba 100644
--- a/src/Shaders/compatibility.glsl
+++ b/src/Shaders/compatibility.glsl
@@ -12,3 +12,10 @@
 #if defined(GL_ES) && __VERSION__ >= 300
 #define EXPLICIT_ATTRIB_LOCATION
 #endif
+
+/* Precision qualifiers are not supported in GLSL 1.20 */
+#if !defined(GL_ES) && __VERSION__ == 120
+#define highp
+#define mediump
+#define lowp
+#endif