RenderTexture.h

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#ifndef RENDER_TEXTURE__H
#define RENDER_TEXTURE__H
#include "shared/pbuffer.h"

// simple wrapper to encapsulate a pbuffer using render-to-texture and its associated texture object
// v1.1 - updated to work with multiple draw buffers

class RenderTexture {
public:
   RenderTexture(char *strMode, int iWidth, int iHeight, GLenum target) : m_target(target)
   {
      m_pbuffer = new PBuffer(strMode);
      m_pbuffer->Initialize(iWidth, iHeight, false, true);

        for(int i=0; i<max_buffers; i++) {
            m_tex[i] = 0;
        }
   };

   ~RenderTexture()
   {
      delete m_pbuffer;
        for(int i=0; i<max_buffers; i++) {
            if (m_tex[i]) {
              glDeleteTextures(1, &m_tex[i]);
            }
        }
   }

   void Activate() { m_pbuffer->Activate(); }
   void Deactivate() { m_pbuffer->Deactivate(); }

   void Bind(int iBuffer=WGL_FRONT_LEFT_ARB)
   {
        int tex_no = iBuffer - WGL_FRONT_LEFT_ARB;
        if (m_tex[tex_no] == 0) {
            // lazily allocate texture objects on demand
            CreateTexture(m_tex[tex_no]);
        }
      glBindTexture(m_target, m_tex[tex_no]);
      m_pbuffer->Bind(iBuffer);
   }

   void Release(int iBuffer=WGL_FRONT_LEFT_ARB) {
      glBindTexture(m_target, m_tex[iBuffer - WGL_FRONT_LEFT_ARB]);
      m_pbuffer->Release(iBuffer);
   }

    inline int GetWidth() { return m_pbuffer->GetWidth(); }
    inline int GetHeight() { return m_pbuffer->GetHeight(); }

private:
    void CreateTexture(GLuint &tex)
    {
      glGenTextures(1, &tex);
      glBindTexture(m_target, tex);
      glTexParameteri(m_target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
      glTexParameteri(m_target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
      glTexParameteri(m_target, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
      glTexParameteri(m_target, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    }

    const static int max_buffers = 14;  // WGL_FRONT_LEFT_ARB - WGL_AUX9_ARB
   PBuffer *m_pbuffer;
   GLuint m_tex[max_buffers];          // texture for each buffer
   GLenum m_target;
};
#endif