RenderStreamPBOCopy.java

/*
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package org.lwjgl.util.stream;

import org.lwjgl.opengl.ContextCapabilities;
import org.lwjgl.util.stream.StreamUtil.RenderStreamFactory;

import static org.lwjgl.opengl.GL15.*;
import static org.lwjgl.opengl.GL21.*;
import static org.lwjgl.opengl.GL31.*;

/** Default StreamPBOReader implementation: Asynchronous ReadPixels to PBOs */
final class RenderStreamPBOCopy extends RenderStreamPBO {

	public static final RenderStreamFactory FACTORY = new RenderStreamFactory("ARB_copy_buffer") {
		public boolean isSupported(final ContextCapabilities caps) {
			return RenderStreamPBODefault.FACTORY.isSupported(caps)
			       && caps.GL_ARB_copy_buffer
			       && caps.GL_NV_gpu_program5 // Nvidia only
			       && (caps.OpenGL40 || caps.GL_ARB_tessellation_shader) // Fermi+
				;
		}

		public RenderStream create(final StreamHandler handler, final int samples, final int transfersToBuffer) {
			return new RenderStreamPBOCopy(handler, samples, transfersToBuffer, ReadbackType.GET_TEX_IMAGE);
		}
	};

	private int devicePBO;

	RenderStreamPBOCopy(final StreamHandler handler, final int samples, final int transfersToBuffer, final ReadbackType readbackType) {
		super(handler, samples, transfersToBuffer, readbackType);
	}

	protected void resizeBuffers(final int height, final int stride) {
		super.resizeBuffers(height, stride);

		devicePBO = glGenBuffers();

		glBindBuffer(GL_PIXEL_PACK_BUFFER, devicePBO);
		glBufferData(GL_PIXEL_PACK_BUFFER, height * stride, GL_STREAM_COPY); // Should allocate device memory
		glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
	}

	protected void readBack(final int index) {
		glBindBuffer(GL_PIXEL_PACK_BUFFER, devicePBO);

		super.readBack(index);

		glBindBuffer(GL_COPY_WRITE_BUFFER, pbos[index]);

		glCopyBufferSubData(GL_PIXEL_PACK_BUFFER, GL_COPY_WRITE_BUFFER, 0, 0, height * stride);

		glBindBuffer(GL_COPY_WRITE_BUFFER, 0);
		glBindBuffer(GL_COPY_READ_BUFFER, 0);
	}

	protected void pinBuffer(final int index) {
		glBindBuffer(GL_PIXEL_PACK_BUFFER, pbos[index]);

		// We don't need to manually synchronized here, MapBuffer will block until ReadPixels above has finished.
		// The buffer will be unmapped in waitForProcessingToComplete
		pinnedBuffers[index] = glMapBuffer(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY, height * stride, pinnedBuffers[index]);

		glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
	}

	protected void copyFrames(final int src, final int trg) {
		glBindBuffer(GL_PIXEL_PACK_BUFFER, pbos[src]);
		glBindBuffer(GL_COPY_WRITE_BUFFER, pbos[trg]);

		glCopyBufferSubData(GL_PIXEL_PACK_BUFFER, GL_COPY_WRITE_BUFFER, 0, 0, height * stride);

		glBindBuffer(GL_COPY_WRITE_BUFFER, 0);
		glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
	}

	protected void postProcess(final int index) {
		glUnmapBuffer(GL_PIXEL_PACK_BUFFER);
	}

	protected void destroyObjects() {
		glDeleteBuffers(devicePBO);
		super.destroyObjects();
	}
}