org.terasology.rendering.dag.nodes.OutputToHMDNode.java Source code

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Here is the source code for org.terasology.rendering.dag.nodes.OutputToHMDNode.java

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/*
 * Copyright 2017 MovingBlocks
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.terasology.rendering.dag.nodes;

import jopenvr.JOpenVRLibrary;
import org.lwjgl.opengl.GL11;
import org.terasology.assets.ResourceUrn;
import org.terasology.config.Config;
import org.terasology.context.Context;
import org.terasology.engine.SimpleUri;
import org.terasology.monitoring.PerformanceMonitor;
import org.terasology.rendering.dag.ConditionDependentNode;
import org.terasology.rendering.dag.stateChanges.EnableMaterial;
import org.terasology.rendering.opengl.FBO;
import org.terasology.rendering.opengl.FBOConfig;
import org.terasology.rendering.opengl.fbms.DisplayResolutionDependentFBOs;
import org.terasology.rendering.openvrprovider.OpenVRProvider;
import org.terasology.rendering.world.WorldRenderer;
import org.terasology.rendering.world.WorldRenderer.RenderingStage;

import static org.lwjgl.opengl.EXTFramebufferObject.GL_FRAMEBUFFER_EXT;
import static org.lwjgl.opengl.EXTFramebufferObject.glBindFramebufferEXT;
import static org.lwjgl.opengl.GL11.GL_COLOR_BUFFER_BIT;
import static org.lwjgl.opengl.GL11.GL_DEPTH_BUFFER_BIT;
import static org.lwjgl.opengl.GL11.glClear;
import static org.terasology.rendering.opengl.OpenGLUtils.renderFullscreenQuad;
import static org.terasology.rendering.opengl.ScalingFactors.FULL_SCALE;
import static org.terasology.rendering.opengl.fbms.DisplayResolutionDependentFBOs.FINAL_BUFFER;

public class OutputToHMDNode extends ConditionDependentNode {
    private static final SimpleUri LEFT_EYE_FBO_URI = new SimpleUri("engine:fbo.leftEye");
    private static final SimpleUri RIGHT_EYE_FBO_URI = new SimpleUri("engine:fbo.rightEye");
    private static final ResourceUrn DEFAULT_TEXTURED_MATERIAL_URN = new ResourceUrn("engine:prog.defaultTextured");
    // TODO: make these configurable options

    private OpenVRProvider vrProvider;
    private WorldRenderer worldRenderer;

    private FBO leftEyeFbo;
    private FBO rightEyeFbo;
    private FBO finalFbo;

    /**
     * Constructs an instance of this node. Specifically, initialize the vrProvider and pass the frame buffer
     * information for the vrProvider to use.
     */
    public OutputToHMDNode(Context context) {
        super(context);

        vrProvider = context.get(OpenVRProvider.class);
        requiresCondition(
                () -> (context.get(Config.class).getRendering().isVrSupport() && vrProvider.isInitialized()));

        if (this.isEnabled()) {
            worldRenderer = context.get(WorldRenderer.class);

            DisplayResolutionDependentFBOs displayResolutionDependentFBOs = context
                    .get(DisplayResolutionDependentFBOs.class);
            leftEyeFbo = requiresFBO(new FBOConfig(LEFT_EYE_FBO_URI, FULL_SCALE, FBO.Type.DEFAULT).useDepthBuffer(),
                    displayResolutionDependentFBOs);
            rightEyeFbo = requiresFBO(
                    new FBOConfig(RIGHT_EYE_FBO_URI, FULL_SCALE, FBO.Type.DEFAULT).useDepthBuffer(),
                    displayResolutionDependentFBOs);
            finalFbo = displayResolutionDependentFBOs.get(FINAL_BUFFER);

            vrProvider.texType[0].handle = leftEyeFbo.getColorBufferTextureId();
            vrProvider.texType[0].eColorSpace = JOpenVRLibrary.EColorSpace.EColorSpace_ColorSpace_Gamma;
            vrProvider.texType[0].eType = JOpenVRLibrary.EGraphicsAPIConvention.EGraphicsAPIConvention_API_OpenGL;
            vrProvider.texType[0].write();
            vrProvider.texType[1].handle = rightEyeFbo.getColorBufferTextureId();
            vrProvider.texType[1].eColorSpace = JOpenVRLibrary.EColorSpace.EColorSpace_ColorSpace_Gamma;
            vrProvider.texType[1].eType = JOpenVRLibrary.EGraphicsAPIConvention.EGraphicsAPIConvention_API_OpenGL;
            vrProvider.texType[1].write();

            addDesiredStateChange(new EnableMaterial(DEFAULT_TEXTURED_MATERIAL_URN));
        }
    }

    /**
     * Actually perform the rendering-related tasks.
     */
    @Override
    public void process() {
        PerformanceMonitor.startActivity("rendering/outputToHMD");
        finalFbo.bindTexture();
        renderFinalStereoImage(worldRenderer.getCurrentRenderStage());
        PerformanceMonitor.endActivity();
    }

    private void renderFinalStereoImage(RenderingStage renderingStage) {
        // TODO: verify if we can use glCopyTexSubImage2D instead of pass-through shaders,
        // TODO: in terms of code simplicity and performance.
        switch (renderingStage) {
        case LEFT_EYE:
            vrProvider.updateState();
            leftEyeFbo.bind();
            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
            renderFullscreenQuad();
            break;

        case RIGHT_EYE:
            rightEyeFbo.bind();
            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
            renderFullscreenQuad();
            vrProvider.submitFrame();
            GL11.glFinish();
            break;
        }

        // Bind the default FBO. The DAG does not recognize that this node has
        // bound a different FBO, so as far as it is concerned, FBO 0 is still
        // bound. As a result, without the below line, the image is only copied
        // to the HMD - not to the screen as we would like. To get around this,
        // we bind the default FBO here at the end.  This is a bit brittle
        // because it assumes that FBO 0 is bound before this node is run.
        // TODO: break this node into two different nodes that use addDesiredStateChange(BindFbo...))
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
    }
}