[PATCH v6 3/6] gles: track gl buffer contents in a shadow buffer

[Imre Deak]

This is needed since GLES/GLES2 don't support either glGetBufferSubData
or glMapBufferOES. At the moment apitrace is only interested in
GL_ELEMENT_ARRAY_BUFFER contents so don't track buffers of other types.

Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 helpers/glsize.hpp   |    7 ++++-
 wrappers/gltrace.hpp |   29 ++++++++++++++++++
 wrappers/gltrace.py  |   81 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 116 insertions(+), 1 deletion(-)

diff --git a/helpers/glsize.hpp b/helpers/glsize.hpp
index 6ffba68..df9aad3 100644
--- a/helpers/glsize.hpp
+++ b/helpers/glsize.hpp
@@ -332,6 +332,11 @@ _glDrawArrays_count(GLint first, GLsizei count)
 
 #define _glDrawArraysEXT_count _glDrawArrays_count
 
+/* Forward declaration for definition in gltrace.py */
+void
+_shadow_glGetBufferSubData(GLenum target, GLintptr offset, GLsizeiptr size,
+                              GLvoid *data);
+
 static inline GLuint
 _glDrawElementsBaseVertex_count(GLsizei count, GLenum type, const GLvoid *indices, GLint basevertex)
 {
@@ -352,7 +357,7 @@ _glDrawElementsBaseVertex_count(GLsizei count, GLenum type, const GLvoid *indice
             return 0;
         }
         memset(temp, 0, size);
-        _glGetBufferSubData(GL_ELEMENT_ARRAY_BUFFER, offset, size, temp);
+        _shadow_glGetBufferSubData(GL_ELEMENT_ARRAY_BUFFER, offset, size, temp);
         indices = temp;
     } else {
         if (!indices) {
diff --git a/wrappers/gltrace.hpp b/wrappers/gltrace.hpp
index db824bb..155f827 100644
--- a/wrappers/gltrace.hpp
+++ b/wrappers/gltrace.hpp
@@ -28,6 +28,9 @@
 
 
 #include "glimports.hpp"
+#include <string.h>
+#include <stdlib.h>
+#include <map>
 
 
 namespace gltrace {
@@ -39,6 +42,25 @@ enum Profile {
     PROFILE_ES2,
 };
 
+class Buffer {
+public:
+    ~Buffer()
+    {
+        free(data);
+    }
+
+    void resetData(const void *new_data, size_t new_size)
+    {
+        data = realloc(data, new_size);
+        size = new_size;
+        if (size)
+            memcpy(data, new_data, size);
+    }
+
+	size_t size;
+	void *data;
+};
+
 class Context {
 public:
     enum Profile profile;
@@ -46,6 +68,7 @@ public:
     bool user_arrays_arb;
     bool user_arrays_nv;
     unsigned retain_count;
+    std::map <GLuint, class Buffer *> buffers;
 
     Context(void) :
         profile(PROFILE_COMPAT),
@@ -54,6 +77,12 @@ public:
         user_arrays_nv(false),
         retain_count(0)
     { }
+
+    inline bool
+    needsShadowBuffers(void)
+    {
+        return profile == PROFILE_ES1 || profile == PROFILE_ES2;
+    }
 };
 
 void
diff --git a/wrappers/gltrace.py b/wrappers/gltrace.py
index 411a19b..b97929e 100644
--- a/wrappers/gltrace.py
+++ b/wrappers/gltrace.py
@@ -141,6 +141,8 @@ class GlTracer(Tracer):
         print '}'
         print
 
+        self.defineShadowBufferHelper()
+
         # Whether we need user arrays
         print 'static inline bool _need_user_arrays(void)'
         print '{'
@@ -349,6 +351,81 @@ class GlTracer(Tracer):
         else:
             Tracer.traceApi(self, api)
 
+    def defineShadowBufferHelper(self):
+        print 'void _shadow_glGetBufferSubData(GLenum target, GLintptr offset,'
+        print '                                GLsizeiptr size, GLvoid *data)'
+        print '{'
+        print '    struct gltrace::Context *ctx = gltrace::getContext();'
+        print '    if (!ctx->needsShadowBuffers() || target != GL_ELEMENT_ARRAY_BUFFER) {'
+        print '        glGetBufferSubData(target, offset, size, data);'
+        print '        return;'
+        print '    }'
+        print
+        print '    struct gltrace::Buffer *buf;'
+        print '    GLint buf_id;'
+        print
+        print '    glGetIntegerv(GL_ELEMENT_ARRAY_BUFFER_BINDING, &buf_id);'
+        print '    buf = ctx->buffers[buf_id];'
+        print '    assert(size + offset <= buf->size);'
+        print '    memcpy(data, (uint8_t *)buf->data + offset, size);'
+        print '}'
+
+    def shadowBufferProlog(self, function):
+        if function.name == 'glBufferData':
+            print '    gltrace::Context *ctx = gltrace::getContext();'
+            print '    if (ctx->needsShadowBuffers() && target == GL_ELEMENT_ARRAY_BUFFER) {'
+            print '        struct gltrace::Buffer *buf;'
+            print '        GLint buf_id;'
+            print
+            print '        glGetIntegerv(GL_ELEMENT_ARRAY_BUFFER_BINDING, &buf_id);'
+            print '        buf = ctx->buffers[buf_id];'
+            print '        buf->resetData(data, size);'
+            print '    }'
+            print
+
+        if function.name == 'glBufferSubData':
+            print '    gltrace::Context *ctx = gltrace::getContext();'
+            print '    if (ctx->needsShadowBuffers() && target == GL_ELEMENT_ARRAY_BUFFER) {'
+            print '        struct gltrace::Buffer *buf;'
+            print '        GLint buf_id;'
+            print
+            print '        glGetIntegerv(GL_ELEMENT_ARRAY_BUFFER_BINDING, &buf_id);'
+            print '        buf = ctx->buffers[buf_id];'
+            print '        memcpy((uint8_t *)buf->data + offset, data, size);'
+            print '    }'
+            print
+
+        if function.name == 'glDeleteBuffers':
+            print '    gltrace::Context *ctx = gltrace::getContext();'
+            print '    if (ctx->needsShadowBuffers()) {'
+            print '        int i;'
+            print
+            print '        for (i = 0; i < n; i++) {'
+            print '            unsigned long buf_id;'
+            print '            struct gltrace::Buffer *buf;'
+            print
+            print '            buf_id = buffer[i];'
+            print '            buf = ctx->buffers[buf_id];'
+            print '            if (buf) {'
+            print '                ctx->buffers.erase(buf_id);'
+            print '                delete buf;'
+            print '            }'
+            print '        }'
+            print '    }'
+
+    def shadowBufferEpilog(self, function):
+        if function.name == 'glGenBuffers':
+            print '    gltrace::Context *ctx = gltrace::getContext();'
+            print '    if (ctx->needsShadowBuffers()) {'
+            print '        int i;'
+            print '        for (i = 0; i < n; i++) {'
+            print '            GLuint buf_id = buffer[i];'
+            print '            ctx->buffers[buf_id] = new gltrace::Buffer;'
+            print '        }'
+            print '    }'
+            print
+
+
     array_pointer_function_names = set((
         "glVertexPointer",
         "glNormalPointer",
@@ -632,8 +709,12 @@ class GlTracer(Tracer):
             print '        }'
             print '    }'
 
+        self.shadowBufferProlog(function)
+
         Tracer.traceFunctionImplBody(self, function)
 
+        self.shadowBufferEpilog(function)
+
     marker_functions = [
         # GL_GREMEDY_string_marker
         'glStringMarkerGREMEDY',
-- 
1.7.9.5