From 8c4d02ef875518be21f63bd115a0bec813da5a91 Mon Sep 17 00:00:00 2001
From: Sean Harmer <sean.harmer@kdab.com>
Date: Fri, 1 Mar 2013 16:32:04 +0000
Subject: [PATCH] OpenGL: Add support for the Compute shader stage
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Change-Id: Ibb1b79358758c2adf818af8c6fcd5c379efad8c3
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>
---
 src/gui/opengl/qopengl.h                |  1 +
 src/gui/opengl/qopenglshaderprogram.cpp | 15 ++++++++++++++-
 src/gui/opengl/qopenglshaderprogram.h   |  3 ++-
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/gui/opengl/qopengl.h b/src/gui/opengl/qopengl.h
index df63eac1f7..e4e06ba284 100644
--- a/src/gui/opengl/qopengl.h
+++ b/src/gui/opengl/qopengl.h
@@ -108,6 +108,7 @@ typedef GLfloat GLdouble;
 # endif
 #if !defined(Q_OS_MAC)
 #  define QT_OPENGL_4
+#  define QT_OPENGL_4_3
 #endif
 #endif
 
diff --git a/src/gui/opengl/qopenglshaderprogram.cpp b/src/gui/opengl/qopenglshaderprogram.cpp
index e48b922dac..1cde0cb92d 100644
--- a/src/gui/opengl/qopenglshaderprogram.cpp
+++ b/src/gui/opengl/qopenglshaderprogram.cpp
@@ -156,6 +156,8 @@ QT_BEGIN_NAMESPACE
            shading language (GLSL), based on the core feature (requires OpenGL >= 4.0).
     \value TessellationEvaluation Tessellation evaluation shaders written in the OpenGL
            shading language (GLSL), based on the core feature (requires OpenGL >= 4.0).
+    \value Compute Compute shaders written in the OpenGL shading language (GLSL),
+           based on the core feature (requires OpenGL >= 4.3).
 */
 
 class QOpenGLShaderPrivate : public QObjectPrivate
@@ -235,6 +237,10 @@ bool QOpenGLShaderPrivate::create()
         shader = glfuncs->glCreateShader(GL_TESS_CONTROL_SHADER);
     } else if (shaderType == QOpenGLShader::TessellationEvaluation && supportsTessellationShaders) {
         shader = glfuncs->glCreateShader(GL_TESS_EVALUATION_SHADER);
+#endif
+#if defined(QT_OPENGL_4_3)
+    } else if (shaderType == QOpenGLShader::Compute) {
+        shader = glfuncs->glCreateShader(GL_COMPUTE_SHADER);
 #endif
     } else {
         shader = glfuncs->glCreateShader(GL_FRAGMENT_SHADER);
@@ -3230,7 +3236,7 @@ bool QOpenGLShader::hasOpenGLShaders(ShaderType type, QOpenGLContext *context)
     if (!context)
         return false;
 
-    if ((type & ~(Geometry | Vertex | Fragment | TessellationControl | TessellationEvaluation)) || type == 0)
+    if ((type & ~(Geometry | Vertex | Fragment | TessellationControl | TessellationEvaluation | Compute)) || type == 0)
         return false;
 
     QSurfaceFormat format = context->format();
@@ -3249,6 +3255,13 @@ bool QOpenGLShader::hasOpenGLShaders(ShaderType type, QOpenGLContext *context)
 #else
         // No tessellation shader support in OpenGL ES2
         return false;
+#endif
+    } else if (type == Compute) {
+#if defined(QT_OPENGL_4_3)
+        return (format.version() >= qMakePair<int, int>(4, 3));
+#else
+        // No compute shader support without OpenGL 4.3 or newer
+        return false;
 #endif
     }
 
diff --git a/src/gui/opengl/qopenglshaderprogram.h b/src/gui/opengl/qopenglshaderprogram.h
index 3677779a6a..6c3dd37843 100644
--- a/src/gui/opengl/qopenglshaderprogram.h
+++ b/src/gui/opengl/qopenglshaderprogram.h
@@ -67,7 +67,8 @@ public:
         Fragment               = 0x0002,
         Geometry               = 0x0004,
         TessellationControl    = 0x0008,
-        TessellationEvaluation = 0x0010
+        TessellationEvaluation = 0x0010,
+        Compute                = 0x0020
     };
     Q_DECLARE_FLAGS(ShaderType, ShaderTypeBit)