Store white noise background pixels in pixel buffer objects

dicarlolab-mworks · Jan 25, 2011 · 0cc4291 · 0cc4291
1 parent 2a637c9
commit 0cc4291
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Showing 2 changed files with 66 additions and 8 deletions.
diff --git a/WhiteNoiseBackground/WhiteNoiseBackground.cpp b/WhiteNoiseBackground/WhiteNoiseBackground.cpp
@@ -31,15 +31,33 @@ void WhiteNoiseBackground::load(shared_ptr<StimulusDisplay> display) {
         GLint width, height;
         display->getCurrentViewportSize(width, height);
         dims[i] = DisplayDimensions(width, height);
-        if (i == 0) {
-            pixels.resize(width * height);
-        }
+
+        glGenBuffers(1, &(buffers[i]));
+        glBindBuffer(GL_PIXEL_UNPACK_BUFFER, buffers[i]);
+        glBufferData(GL_PIXEL_UNPACK_BUFFER, (width * height * sizeof(PixelType)), NULL, GL_DYNAMIC_DRAW);
+        glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
     }
 
     loaded = true;
 }
 
 
+void WhiteNoiseBackground::unload(shared_ptr<StimulusDisplay> display) {
+    if (!loaded)
+        return;
+
+    for (int i = 0; i < display->getNContexts(); i++) {
+        display->setCurrent(i);
+        glDeleteBuffers(1, &(buffers[i]));
+    }
+
+    dims.clear();
+    buffers.clear();
+
+    loaded = false;
+}
+
+
 void WhiteNoiseBackground::draw(shared_ptr<StimulusDisplay> display) {
     glPushClientAttrib(GL_CLIENT_PIXEL_STORE_BIT);
 
@@ -53,9 +71,13 @@ void WhiteNoiseBackground::draw(shared_ptr<StimulusDisplay> display) {
     glPixelStorei(GL_UNPACK_SKIP_IMAGES, 0);
     glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
 
-    DisplayDimensions &currentDims = dims[display->getCurrentContextIndex()];
+    int index = display->getCurrentContextIndex();
+    DisplayDimensions &currentDims = dims[index];
     glWindowPos2i(0, 0);
-    glDrawPixels(currentDims.first, currentDims.second, GL_LUMINANCE, PIXEL_TYPE, &(pixels[0]));
+
+    glBindBuffer(GL_PIXEL_UNPACK_BUFFER, buffers[index]);
+    glDrawPixels(currentDims.first, currentDims.second, GL_LUMINANCE, PIXEL_TYPE, (GLvoid *)0);
+    glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
 
     glPopClientAttrib();
 }
@@ -69,8 +91,21 @@ Datum WhiteNoiseBackground::getCurrentAnnounceDrawData() {
 
 
 void WhiteNoiseBackground::randomizePixels() {
-    for (size_t i = 0; i < pixels.size(); i++) {
-        pixels[i] = randDist();
+    shared_ptr<StimulusDisplay> display(StimulusDisplay::getCurrentStimulusDisplay());
+
+    for (int i = 0; i < display->getNContexts(); i++) {
+        display->setCurrent(i);
+        DisplayDimensions &currentDims = dims[i];
+
+        glBindBuffer(GL_PIXEL_UNPACK_BUFFER, buffers[i]);
+        PixelType *pixels = (PixelType *)glMapBuffer(GL_PIXEL_UNPACK_BUFFER, GL_WRITE_ONLY);
+
+        for (size_t i = 0; i < (currentDims.first * currentDims.second); i++) {
+            pixels[i] = randDist();
+        }
+
+        glUnmapBuffer(GL_PIXEL_UNPACK_BUFFER);
+        glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
     }
 }
 

diff --git a/WhiteNoiseBackground/WhiteNoiseBackground.h b/WhiteNoiseBackground/WhiteNoiseBackground.h
@@ -25,6 +25,7 @@ class WhiteNoiseBackground : public Stimulus {
     virtual ~WhiteNoiseBackground();
 
     virtual void load(shared_ptr<StimulusDisplay> display);
+    virtual void unload(shared_ptr<StimulusDisplay> display);
     virtual void draw(shared_ptr<StimulusDisplay> display);
     virtual Datum getCurrentAnnounceDrawData();
 
@@ -38,7 +39,7 @@ class WhiteNoiseBackground : public Stimulus {
     typedef GLfloat PixelType;
 
     std::map<int, DisplayDimensions> dims;
-    std::vector<PixelType> pixels;
+    std::map<int, GLuint> buffers;
 
     boost::mt19937 randGen;
     boost::uniform_01< boost::mt19937&, PixelType > randDist;
@@ -47,3 +48,25 @@ class WhiteNoiseBackground : public Stimulus {
 
 
 #endif
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