/* <copyright>
This file contains proprietary software owned by Motorola Mobility, Inc.<br/>
No rights, expressed or implied, whatsoever to this software are provided by Motorola Mobility, Inc. hereunder.<br/>
(c) Copyright 2011 Motorola Mobility, Inc.  All Rights Reserved.
</copyright> */

var RDGE = RDGE || {};
RDGE.fx = RDGE.fx || {};

/**
* Implements SSAO.
* See http://www.gamedev.net/page/resources/_/reference/programming/140/lighting-and-shading/a-simple-and-practical-approach-to-ssao-r2753
* @param v2ScreenSize - size of the viewport in window coordinates
*/
RDGE.fx.fxSSAO = function (enHRDepth) {
    function renderInitSSAO(quad) {
        quad.shader = RDGE.createShader(RDGE.globals.gl, 'ssao_vshader', enHRDepth ? 'ssaohr_fshader' : 'ssao_fshader', ["vert", "texcoord"]);
        quad.renderObj = new RDGE.RenderObject(quad.shader);

        var quadBuf = getScreenAlignedQuad();
        quad.vertBuffer = quadBuf.vertexObject;
        quad.uvBuffer = quadBuf.texCoordObject;

        quad.renderObj.addTexture("sColMap", 0, RDGE.UNIFORMTYPE.TEXTURE2D);
        quad.renderObj.addTexture("sNormDepthMap", 1, RDGE.UNIFORMTYPE.TEXTURE2D);
        quad.renderObj.addTexture("sRandMap", 2, RDGE.UNIFORMTYPE.TEXTURE2D);
        if (enHRDepth)
            quad.renderObj.addTexture("sHRDepthMap", 3, RDGE.UNIFORMTYPE.TEXTURE2D);

        quad.renderObj.addBuffers(quad.vertBuffer, RDGE.globals.gl.ARRAY_BUFFER, 3, 0, RDGE.globals.gl.FLOAT);
        quad.renderObj.addBuffers(quad.uvBuffer, RDGE.globals.gl.ARRAY_BUFFER, 2, 2, RDGE.globals.gl.FLOAT);
    };

    // Load random normal texture
    this.randTexture = createTexture(RDGE.globals.gl, RDGE.globals.engine._assetPath + "images/random_normal.png");
    RDGE.globals.gl.bindTexture(RDGE.globals.gl.TEXTURE_2D, this.randTexture);
    RDGE.globals.gl.texParameteri(RDGE.globals.gl.TEXTURE_2D, RDGE.globals.gl.TEXTURE_MIN_FILTER, RDGE.globals.gl.LINEAR);
    RDGE.globals.gl.texParameteri(RDGE.globals.gl.TEXTURE_2D, RDGE.globals.gl.TEXTURE_WRAP_S, RDGE.globals.gl.REPEAT);
    RDGE.globals.gl.texParameteri(RDGE.globals.gl.TEXTURE_2D, RDGE.globals.gl.TEXTURE_WRAP_T, RDGE.globals.gl.REPEAT);

    // Whether or not to use a high res depth texture
    this.enHRDepth = enHRDepth;

    // Quad for full screen pass
    this.ssaoQuad = new RDGE.ScreenQuad(null);
    this.ssaoQuad.initialize(renderInitSSAO);

    // Set up uniforms
    var activeCam = g_cameraManager.getActiveCamera();
    this.v3FrustumFLT = activeCam.getFTR();
    this.ssaoQuad.renderObj.addUniform("u_frustumFLT", this.v3FrustumFLT, RDGE.UNIFORMTYPE.FLOAT3);

    this.v4ArtVals = [1.0, 1.0, 1.0, 1.0];
    this.ssaoQuad.renderObj.addUniform("u_artVals", this.v4ArtVals, RDGE.UNIFORMTYPE.FLOAT4);

    this.fRandMapSize = 64.0;
    this.ssaoQuad.renderObj.addUniform("u_randMapSize", this.fRandMapSize, RDGE.UNIFORMTYPE.FLOAT);

    this.v2ScreenSize = [1024, 1024];
    this.ssaoQuad.renderObj.addUniform("u_screenSize", this.v2ScreenSize, RDGE.UNIFORMTYPE.FLOAT2);
};

/**
* Contributes SSAO to the passed offscreen surface, rendering to another surface.
* See http://www.gamedev.net/page/resources/_/reference/programming/140/lighting-and-shading/a-simple-and-practical-approach-to-ssao-r2753
* @param srcTexColor - color surface of rendered scene
* @param srcTexNormDepth - screenspace normal+depth surface for scene; {nx, ny, nz, depth}
* @param dstRenderTarget - where to put the result of SSAO
* @param sampleRadius - 
* @param intensity - 
* @param distScale - 
* @param bias - 
*/
RDGE.fx.fxSSAO.prototype.doSSAO = function (srcTexColor, srcTexNormDepth, srcTexHRDepth, dstRenderTarget, sampleRadius, intensity, distScale, bias) {
    // Set art params and other uniforms
    this.v4ArtVals[0] = sampleRadius;
    this.v4ArtVals[1] = intensity;
    this.v4ArtVals[2] = distScale;
    this.v4ArtVals[3] = bias;

    this.v2ScreenSize[0] = dstRenderTarget ? dstRenderTarget.frameBuffer.width : RDGE.globals.width;
    this.v2ScreenSize[1] = dstRenderTarget ? dstRenderTarget.frameBuffer.height : RDGE.globals.height;

    // Do ssao
    RDGE.globals.gl.bindFramebuffer(RDGE.globals.gl.FRAMEBUFFER, dstRenderTarget ? dstRenderTarget.frameBuffer : null);
    // gl.viewport(0, 0, 99999, 99999);
    RDGE.globals.gl.clear(RDGE.globals.gl.COLOR_BUFFER_BIT);

    RDGE.globals.gl.disable(RDGE.globals.gl.DEPTH_TEST);

    RDGE.globals.gl.useProgram(this.ssaoQuad.shader);

    this.ssaoQuad.renderObj.bindBuffers();
    this.ssaoQuad.renderObj.bindTextures();
    this.ssaoQuad.renderObj.bindUniforms();

    RDGE.globals.gl.activeTexture(RDGE.globals.gl.TEXTURE0);
    RDGE.globals.gl.bindTexture(RDGE.globals.gl.TEXTURE_2D, srcTexColor);
    RDGE.globals.gl.activeTexture(RDGE.globals.gl.TEXTURE1);
    RDGE.globals.gl.bindTexture(RDGE.globals.gl.TEXTURE_2D, srcTexNormDepth);
    RDGE.globals.gl.activeTexture(RDGE.globals.gl.TEXTURE2);
    RDGE.globals.gl.bindTexture(RDGE.globals.gl.TEXTURE_2D, this.randTexture);
    if (this.enHRDepth) {
        RDGE.globals.gl.activeTexture(RDGE.globals.gl.TEXTURE3);
        RDGE.globals.gl.bindTexture(RDGE.globals.gl.TEXTURE_2D, srcTexHRDepth);
    }
    RDGE.globals.gl.activeTexture(RDGE.globals.gl.TEXTURE0);

    RDGE.globals.gl.drawArrays(RDGE.globals.gl.TRIANGLES, 0, 6);

    RDGE.globals.gl.enable(RDGE.globals.gl.DEPTH_TEST);
    RDGE.globals.gl.useProgram(null);

    return dstRenderTarget;
};