/*
  ==============================================================================

   This file is part of the JUCE library - "Jules' Utility Class Extensions"
   Copyright 2004-11 by Raw Material Software Ltd.

  ------------------------------------------------------------------------------

   JUCE can be redistributed and/or modified under the terms of the GNU General
   Public License (Version 2), as published by the Free Software Foundation.
   A copy of the license is included in the JUCE distribution, or can be found
   online at www.gnu.org/licenses.

   JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

  ------------------------------------------------------------------------------

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.rawmaterialsoftware.com/juce for more information.

  ==============================================================================
*/

BEGIN_JUCE_NAMESPACE

void OpenGLHelpers::resetErrorState()
{
    while (glGetError() != GL_NO_ERROR) {}
}

void OpenGLHelpers::clear (const Colour& colour)
{
    glClearColor (colour.getFloatRed(), colour.getFloatGreen(),
                  colour.getFloatBlue(), colour.getFloatAlpha());

    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
}

void OpenGLHelpers::setColour (const Colour& colour)
{
    glColor4f (colour.getFloatRed(), colour.getFloatGreen(),
               colour.getFloatBlue(), colour.getFloatAlpha());
}

void OpenGLHelpers::prepareFor2D (int width, int height)
{
    glMatrixMode (GL_PROJECTION);
    glLoadIdentity();

   #if JUCE_OPENGL_ES
    glOrthof (0.0f, (float) width, 0.0f, (float) height, 0.0f, 1.0f);
   #else
    glOrtho  (0.0, width, 0.0, height, 0, 1);
   #endif

    glViewport (0, 0, width, height);
}

void OpenGLHelpers::setPerspective (double fovy, double aspect, double zNear, double zFar)
{
    glLoadIdentity();

   #if JUCE_OPENGL_ES
    const float ymax = (float) (zNear * tan (fovy * double_Pi / 360.0));
    const float ymin = -ymax;

    glFrustumf (ymin * (float) aspect, ymax * (float) aspect, ymin, ymax, (float) zNear, (float) zFar);
   #else
    const double ymax = zNear * tan (fovy * double_Pi / 360.0);
    const double ymin = -ymax;

    glFrustum  (ymin * aspect, ymax * aspect, ymin, ymax, zNear, zFar);
   #endif
}

void OpenGLHelpers::drawQuad2D (float x1, float y1,
                                float x2, float y2,
                                float x3, float y3,
                                float x4, float y4,
                                const Colour& colour)
{
    const GLfloat vertices[]      = { x1, y1, x2, y2, x4, y4, x3, y3 };
    const GLfloat textureCoords[] = { 0, 0, 1.0f, 0, 0, 1.0f, 1.0f, 1.0f };

    setColour (colour);

    glEnableClientState (GL_VERTEX_ARRAY);
    glVertexPointer (2, GL_FLOAT, 0, vertices);

    glEnableClientState (GL_TEXTURE_COORD_ARRAY);
    glTexCoordPointer (2, GL_FLOAT, 0, textureCoords);

    glDisableClientState (GL_COLOR_ARRAY);
    glDisableClientState (GL_NORMAL_ARRAY);

    glDrawArrays (GL_TRIANGLE_STRIP, 0, 4);
}

void OpenGLHelpers::drawQuad3D (float x1, float y1, float z1,
                                float x2, float y2, float z2,
                                float x3, float y3, float z3,
                                float x4, float y4, float z4,
                                const Colour& colour)
{
    const GLfloat vertices[]      = { x1, y1, z1, x2, y2, z2, x4, y4, z4, x3, y3, z3 };
    const GLfloat textureCoords[] = { 0, 0, 1.0f, 0, 0, 1.0f, 1.0f, 1.0f };

    setColour (colour);

    glEnableClientState (GL_VERTEX_ARRAY);
    glVertexPointer (3, GL_FLOAT, 0, vertices);

    glEnableClientState (GL_TEXTURE_COORD_ARRAY);
    glTexCoordPointer (2, GL_FLOAT, 0, textureCoords);

    glDisableClientState (GL_COLOR_ARRAY);
    glDisableClientState (GL_NORMAL_ARRAY);

    glDrawArrays (GL_TRIANGLE_STRIP, 0, 4);
}

END_JUCE_NAMESPACE