RenderTarget.cpp

#include "RenderTarget.h"
#include "Context.h"
#include <math.h>
#include <stdio.h>

#include "Helper.h" // remove this

RenderTarget::Viewport RenderTarget::viewport;

RenderTarget::RenderTarget(GLint width, GLint height, GLint texCount)
{
    rot = 0;

    size.x = width;
    size.y = height;
    this->texCount = texCount;
    windowSize.x = Context::getWindowWidth();
    windowSize.y = Context::getWindowHeight();

    // Create and initialize framebuffer
    texRT = new GLuint[texCount];

    glGenFramebuffers(1, &frameBufferRT);
    glBindFramebuffer(GL_FRAMEBUFFER, frameBufferRT);

    glGenTextures(texCount, texRT);
    for(int i = 0; i < texCount; i ++)
    {
        glBindTexture(GL_TEXTURE_2D, texRT[i]);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + i, GL_TEXTURE_2D, texRT[i], 0);
    }
    glBindFramebuffer(GL_FRAMEBUFFER, 0);

    printf("+ RenderTarget added\n");
}

RenderTarget::~RenderTarget()
{
    printf("- RenderTarget deleted\n");
    delete[] texRT;
}

void RenderTarget::Begin()
{
    // Setup framebuffer
    glGetIntegerv(GL_VIEWPORT, viewport.vp);
    glViewport(0, size.y - windowSize.y, windowSize.x, windowSize.y);
    glBindFramebuffer(GL_FRAMEBUFFER, frameBufferRT);

    if (texCount > 1)
    {
        GLenum* buffers = new GLenum[texCount];
        for (GLuint i = 0; i < texCount; i++)
        {
            buffers[i] = GL_COLOR_ATTACHMENT0 + i;
        }
        glDrawBuffers(texCount, buffers);
        delete[] buffers;
    }

    // Set blend-mode
    glDisable(GL_BLEND);

    // Clear the buffer
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glClear(GL_COLOR_BUFFER_BIT);
}

void RenderTarget::End()
{
    // Reset blend-mode
    glEnable(GL_BLEND);

    // Reset framebuffer
    glBindFramebuffer(GL_FRAMEBUFFER, 0);

    // Reset viewport
    glViewport(viewport.x, viewport.y, viewport.width, viewport.height);
}

void RenderTarget::Draw(GLint x, GLint y)
{
    Draw(x, y, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0, 0, size.x, size.y);
}

void RenderTarget::Draw(GLint x, GLint y, GLfloat alpha)
{
    Draw(x, y, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, alpha, 0, 0, size.x, size.y);
}

void RenderTarget::Draw(GLint x, GLint y, GLfloat rotation, GLfloat scaleX, GLfloat scaleY, GLfloat red, GLfloat green, GLfloat blue, GLfloat alpha, GLint xx, GLint yy, GLint w, GLint h)
{
    // Draw the framebuffer-texture
    // Bind texture
    glBindTexture(GL_TEXTURE_2D, texRT[0]);

    // Push the matrix
    glPushMatrix();

    // Rotate and translate the quad
    glTranslatef(x, y, 0.0f);
    glRotatef(rotation, 0.0f, 0.0f, 1.0f);

    // Calculate coordinates
    GLdouble coX1, coX2, coY1, coY2;
    coX1 = (GLdouble)xx / size.x;
    coY1 = (GLdouble)yy / size.y;
    coX2 = (GLdouble)(xx + w) / size.x;
    coY2 = (GLdouble)(yy + h) / size.y;

    // Testing blend functions
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    // Draw the textured quad
    glBegin(GL_QUADS);
    glColor4f(red, green, blue, alpha);

    glTexCoord2d(coX1, coY2); glVertex2d(0,             0);
    glTexCoord2d(coX2, coY2); glVertex2d(w * scaleX,    0);
    glTexCoord2d(coX2, coY1); glVertex2d(w * scaleX,    h * scaleY);
    glTexCoord2d(coX1, coY1); glVertex2d(0,             h * scaleY);
    //glTexCoord2d(coX1, coY2); glVertex2d(lenDirX(5, rot * 2), lenDirY(5, rot * 3));
    //glTexCoord2d(coX2, coY2); glVertex2d(w * scaleX + lenDirX(5, rot),    lenDirX(5, rot * 4));
    //glTexCoord2d(coX2, coY1); glVertex2d(w * scaleX + lenDirY(5, rot * 4),    h * scaleY + lenDirX(5, rot));
    //glTexCoord2d(coX1, coY1); glVertex2d(lenDirX(-5, rot * 3),                h * scaleY + lenDirX(-5, rot * 2));
    glEnd();

    // Return to default blend-function
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    // Pop the matrix
    glPopMatrix();

    rot += 0.5f;
}

// Get size of rendertarget
Point RenderTarget::GetSize()
{
    return size;
}