SVG text and line elements

[ipdf/code.git] / src / framebuffer.cpp

diff --git a/src/framebuffer.cpp b/src/framebuffer.cpp
index 2302b6c..f3b1bd9 100644 (file)
--- a/src/framebuffer.cpp
+++ b/src/framebuffer.cpp
@@ -7,6 +7,7 @@ void FrameBuffer::Create(int w, int h)
 {
        if (m_render_texture)
        {
+               // FrameBuffer was already Created, destroy it before creating again
                Destroy();
        }
        m_width = w;
@@ -15,7 +16,7 @@ void FrameBuffer::Create(int w, int h)
        glGenFramebuffers(1, &m_render_fbo);
 
        glBindTexture(GL_TEXTURE_2D, m_render_texture);
-       glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
+       glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
 
        glBindFramebuffer(GL_FRAMEBUFFER, m_render_fbo);
 
@@ -27,25 +28,26 @@ void FrameBuffer::Create(int w, int h)
 
 void FrameBuffer::Destroy()
 {
-       if (!m_render_texture) return;
+       if (!m_render_texture) return; // wasn't Created (or already Destroyed)
        glDeleteFramebuffers(1, &m_render_fbo);
        glDeleteTextures(1, &m_render_texture);
 }
 
 void FrameBuffer::Bind()
 {
+       // will draw to this FrameBuffer
        glBindFramebuffer(GL_DRAW_FRAMEBUFFER, m_render_fbo);
 }
 
 void FrameBuffer::UnBind()
 {
-       glBindFramebuffer(GL_FRAMEBUFFER, 0);
+       glBindFramebuffer(GL_FRAMEBUFFER, 0); // will both draw to and read pixels from screen
 }
 
 void FrameBuffer::Blit()
 {
-       glBindFramebuffer(GL_READ_FRAMEBUFFER, m_render_fbo);
-       glBlitFramebuffer(0, 0, m_width, m_height, 0, 0, m_width, m_height, GL_COLOR_BUFFER_BIT, GL_NEAREST);
+       glBindFramebuffer(GL_READ_FRAMEBUFFER, m_render_fbo); // read pixels from this FrameBuffer
+       glBlitFramebuffer(0, 0, m_width, m_height, 0, 0, m_width, m_height, GL_COLOR_BUFFER_BIT, GL_NEAREST); // draw pixels
 }
 
 void FrameBuffer::Clear(float r, float g, float b, float a)