Add Mesa as a GL backend.

http://codereview.appspot.com/4545055/


git-svn-id: http://skia.googlecode.com/svn/trunk@1382 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 128 insertions, 0 deletions

diff --git a/src/utils/mesa/SkEGLContext_Mesa.cpp b/src/utils/mesa/SkEGLContext_Mesa.cpp
new file mode 100644
index 0000000000..ed1b7cd451
--- /dev/null
+++ b/src/utils/mesa/SkEGLContext_Mesa.cpp
@@ -0,0 +1,128 @@
+#include "SkEGLContext.h"
+#include "SkTypes.h"
+
+#include "GL/osmesa.h"
+#include "GL/glu.h"
+
+#define SK_GL_DECL_PROC(T, F) T F ## _func = NULL;
+#define SK_GL_GET_PROC(T, F) F ## _func = (T)OSMesaGetProcAddress(#F);
+#define SK_GL_GET_EXT_PROC(T, F) F ## _func = (T)OSMesaGetProcAddress(#F "EXT");
+
+SkEGLContext::SkEGLContext() : context(NULL), image(NULL) {
+}
+
+SkEGLContext::~SkEGLContext() {
+    if (this->image)
+        free(this->image);
+    
+    if (this->context)
+        OSMesaDestroyContext(this->context);
+}
+
+#if SK_B32_SHIFT < SK_G32_SHIFT &&\
+                   SK_G32_SHIFT < SK_R32_SHIFT &&\
+                                  SK_R32_SHIFT < SK_A32_SHIFT
+    #define SK_OSMESA_COLOR_ORDER OSMESA_BGRA
+#elif SK_R32_SHIFT < SK_G32_SHIFT &&\
+                     SK_G32_SHIFT < SK_B32_SHIFT &&\
+                                    SK_B32_SHIFT < SK_A32_SHIFT
+    #define SK_OSMESA_COLOR_ORDER OSMESA_RGBA
+#elif SK_A32_SHIFT < SK_R32_SHIFT && \
+                     SK_R32_SHIFT < SK_G32_SHIFT && \
+                                    SK_G32_SHIFT < SK_B32_SHIFT
+    #define SK_OSMESA_COLOR_ORDER OSMESA_ARGB
+#else
+    //Color order (rgba) SK_R32_SHIFT SK_G32_SHIFT SK_B32_SHIFT SK_A32_SHIFT
+    #define SK_OSMESA_COLOR_ORDER OSMESA_RGBA
+#endif
+
+bool SkEGLContext::init(const int width, const int height) {
+    /* Create an RGBA-mode context */
+#if OSMESA_MAJOR_VERSION * 100 + OSMESA_MINOR_VERSION >= 305
+    /* specify Z, stencil, accum sizes */
+    OSMesaContext ctx = OSMesaCreateContextExt(SK_OSMESA_COLOR_ORDER, 16, 0, 0, NULL);
+#else
+    OSMesaContext ctx = OSMesaCreateContext(SK_OSMESA_COLOR_ORDER, NULL);
+#endif
+    if (!ctx) {
+        SkDebugf("OSMesaCreateContext failed!\n");
+        return false;
+    }
+    this->context = ctx;
+    
+    // Allocate the image buffer
+    GLfloat *buffer = (GLfloat *) malloc(width * height * 4 * sizeof(GLfloat));
+    if (!buffer) {
+        SkDebugf("Alloc image buffer failed!\n");
+        return false;
+    }
+    this->image = buffer;
+    
+    // Bind the buffer to the context and make it current
+    if (!OSMesaMakeCurrent(ctx, buffer, GL_FLOAT, width, height)) {
+        SkDebugf("OSMesaMakeCurrent failed!\n");
+        return false;
+    }
+    
+    //Setup the framebuffers
+    SK_GL_DECL_PROC(PFNGLGENFRAMEBUFFERSEXTPROC, glGenFramebuffers)
+    SK_GL_DECL_PROC(PFNGLBINDFRAMEBUFFEREXTPROC, glBindFramebuffer)
+    SK_GL_DECL_PROC(PFNGLGENRENDERBUFFERSPROC, glGenRenderbuffers)
+    SK_GL_DECL_PROC(PFNGLBINDRENDERBUFFERPROC, glBindRenderbuffer)
+    SK_GL_DECL_PROC(PFNGLRENDERBUFFERSTORAGEPROC, glRenderbufferStorage)
+    SK_GL_DECL_PROC(PFNGLFRAMEBUFFERRENDERBUFFERPROC, glFramebufferRenderbuffer)
+    SK_GL_DECL_PROC(PFNGLCHECKFRAMEBUFFERSTATUSEXTPROC, glCheckFramebufferStatus)
+    
+    const GLubyte* glExts = glGetString(GL_EXTENSIONS);
+    if (gluCheckExtension(
+          reinterpret_cast<const GLubyte*>("GL_ARB_framebuffer_object")
+          , glExts))
+    {
+        SK_GL_GET_PROC(PFNGLGENFRAMEBUFFERSEXTPROC, glGenFramebuffers)
+        SK_GL_GET_PROC(PFNGLBINDFRAMEBUFFEREXTPROC, glBindFramebuffer)
+        SK_GL_GET_PROC(PFNGLGENRENDERBUFFERSPROC, glGenRenderbuffers)
+        SK_GL_GET_PROC(PFNGLBINDRENDERBUFFERPROC, glBindRenderbuffer)
+        SK_GL_GET_PROC(PFNGLRENDERBUFFERSTORAGEPROC, glRenderbufferStorage)
+        SK_GL_GET_PROC(PFNGLFRAMEBUFFERRENDERBUFFERPROC, glFramebufferRenderbuffer)
+        SK_GL_GET_PROC(PFNGLCHECKFRAMEBUFFERSTATUSEXTPROC, glCheckFramebufferStatus)
+        
+    //osmesa on mac currently only supports EXT
+    } else if (gluCheckExtension(
+          reinterpret_cast<const GLubyte*>("GL_EXT_framebuffer_object")
+          , glExts))
+    {
+        SK_GL_GET_EXT_PROC(PFNGLGENFRAMEBUFFERSEXTPROC, glGenFramebuffers)
+        SK_GL_GET_EXT_PROC(PFNGLBINDFRAMEBUFFEREXTPROC, glBindFramebuffer)
+        SK_GL_GET_EXT_PROC(PFNGLGENRENDERBUFFERSPROC, glGenRenderbuffers)
+        SK_GL_GET_EXT_PROC(PFNGLBINDRENDERBUFFERPROC, glBindRenderbuffer)
+        SK_GL_GET_EXT_PROC(PFNGLRENDERBUFFERSTORAGEPROC, glRenderbufferStorage)
+        SK_GL_GET_EXT_PROC(PFNGLFRAMEBUFFERRENDERBUFFERPROC, glFramebufferRenderbuffer)
+        SK_GL_GET_EXT_PROC(PFNGLCHECKFRAMEBUFFERSTATUSEXTPROC, glCheckFramebufferStatus)
+    } else {
+      SkDebugf("GL_ARB_framebuffer_object not found.\n");
+      return false;
+    }
+    
+    GLuint fboID;
+    GLuint cbID;
+    GLuint dsID;
+    glGenFramebuffers_func(1, &fboID);
+    glBindFramebuffer_func(GL_FRAMEBUFFER, fboID);
+    
+    glGenRenderbuffers_func(1, &cbID);
+    glBindRenderbuffer_func(GL_RENDERBUFFER, cbID);
+    glRenderbufferStorage_func(GL_RENDERBUFFER, OSMESA_RGBA, width, height);
+    glFramebufferRenderbuffer_func(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, cbID);
+    
+    glGenRenderbuffers_func(1, &dsID);
+    glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, dsID);
+    glRenderbufferStorage_func(GL_RENDERBUFFER, GL_STENCIL_INDEX8, width, height);
+    glFramebufferRenderbuffer_func(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, dsID);
+    
+    glViewport(0, 0, width, height);
+    glClearStencil(0);
+    glClear(GL_STENCIL_BUFFER_BIT);
+
+    GLenum status = glCheckFramebufferStatus_func(GL_FRAMEBUFFER);
+    return GL_FRAMEBUFFER_COMPLETE == status;
+}