Don't re-render the display if nothing has changed

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

diff --git a/src/framebuffer.cpp b/src/framebuffer.cpp
new file mode 100644 (file)
index 0000000..88d2cd4
--- /dev/null
+++ b/src/framebuffer.cpp
@@ -0,0 +1,59 @@
+#include "framebuffer.h"
+#define GL_GLEXT_PROTOTYPES
+#include <SDL_opengl.h>
+#include <GL/glext.h>
+
+using namespace IPDF;
+
+void FrameBuffer::Create(int w, int h)
+{
+       if (m_render_texture)
+       {
+               Destroy();
+       }
+       m_width = w;
+       m_height = h;
+       glGenTextures(1, &m_render_texture);
+       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);
+
+       glBindFramebuffer(GL_FRAMEBUFFER, m_render_fbo);
+
+       glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_render_texture, 0);
+
+       glBindFramebuffer(GL_FRAMEBUFFER, 0);
+       glBindTexture(GL_TEXTURE_2D, 0);
+}
+
+void FrameBuffer::Destroy()
+{
+       if (!m_render_texture) return;
+       glDeleteFramebuffers(1, &m_render_fbo);
+       glDeleteTextures(1, &m_render_texture);
+}
+
+void FrameBuffer::Bind()
+{
+       glBindFramebuffer(GL_DRAW_FRAMEBUFFER, m_render_fbo);
+}
+
+void FrameBuffer::UnBind()
+{
+       glBindFramebuffer(GL_FRAMEBUFFER, 0);
+}
+
+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);
+}
+
+void FrameBuffer::Clear(float r, float g, float b, float a)
+{
+       Bind();
+       glClearColor(r,g,b,a);
+       glClear(GL_COLOR_BUFFER_BIT);
+}
+