Initial commit

engines/myst3/gfx_opengl_texture.cpp

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "common/scummsys.h"
+
+#if defined(USE_OPENGL_GAME) || defined(USE_OPENGL_SHADERS)
+
+#include "engines/myst3/gfx_opengl_texture.h"
+
+#include "graphics/opengl/context.h"
+
+namespace Myst3 {
+
+// From Bit Twiddling Hacks
+static uint32 upperPowerOfTwo(uint32 v) {
+	v--;
+	v |= v >> 1;
+	v |= v >> 2;
+	v |= v >> 4;
+	v |= v >> 8;
+	v |= v >> 16;
+	v++;
+	return v;
+}
+
+OpenGLTexture::OpenGLTexture() :
+		internalFormat(0),
+		sourceFormat(0),
+		internalWidth(0),
+		internalHeight(0),
+		upsideDown(false) {
+	glGenTextures(1, &id);
+}
+
+OpenGLTexture::OpenGLTexture(const Graphics::Surface *surface) {
+	width = surface->w;
+	height = surface->h;
+	format = surface->format;
+	upsideDown = false;
+
+	// Pad the textures if non power of two support is unavailable
+	if (OpenGLContext.NPOTSupported) {
+		internalHeight = height;
+		internalWidth = width;
+	} else {
+		internalHeight = upperPowerOfTwo(height);
+		internalWidth = upperPowerOfTwo(width);
+	}
+
+	if (format.bytesPerPixel == 4) {
+		assert(surface->format == getRGBAPixelFormat());
+
+		internalFormat = GL_RGBA;
+		sourceFormat = GL_UNSIGNED_BYTE;
+	} else if (format.bytesPerPixel == 2) {
+		internalFormat = GL_RGB;
+		sourceFormat = GL_UNSIGNED_SHORT_5_6_5;
+	} else
+		error("Unknown pixel format");
+
+	glGenTextures(1, &id);
+	glBindTexture(GL_TEXTURE_2D, id);
+	glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, internalWidth, internalHeight, 0, internalFormat, sourceFormat, nullptr);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+	// TODO: If non power of two textures are unavailable this clamping
+	// has no effect on the padded sides (resulting in white lines on the edges)
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+	update(surface);
+}
+
+OpenGLTexture::~OpenGLTexture() {
+	glDeleteTextures(1, &id);
+}
+
+void OpenGLTexture::update(const Graphics::Surface *surface) {
+	updatePartial(surface, Common::Rect(surface->w, surface->h));
+}
+
+void OpenGLTexture::updateTexture(const Graphics::Surface *surface, const Common::Rect &rect) {
+	assert(surface->format == format);
+
+	glBindTexture(GL_TEXTURE_2D, id);
+
+	if (OpenGLContext.unpackSubImageSupported) {
+		const Graphics::Surface subArea = surface->getSubArea(rect);
+
+		glPixelStorei(GL_UNPACK_ROW_LENGTH, surface->pitch / surface->format.bytesPerPixel);
+
+		glTexSubImage2D(GL_TEXTURE_2D, 0, rect.left, rect.top, subArea.w, subArea.h, internalFormat, sourceFormat, const_cast<void *>(subArea.getPixels()));
+		glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
+	} else {
+		// GL_UNPACK_ROW_LENGTH is not supported, don't bother and do a full texture update
+		glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, surface->w, surface->h, internalFormat, sourceFormat, const_cast<void *>(surface->getPixels()));
+	}
+}
+
+void OpenGLTexture::updatePartial(const Graphics::Surface *surface, const Common::Rect &rect) {
+	updateTexture(surface, rect);
+}
+
+void OpenGLTexture::copyFromFramebuffer(const Common::Rect &screen) {
+	internalFormat = GL_RGB;
+	width  = screen.width();
+	height = screen.height();
+	upsideDown = true;
+
+	// Pad the textures if non power of two support is unavailable
+	if (OpenGLContext.NPOTSupported) {
+		internalHeight = height;
+		internalWidth = width;
+	} else {
+		internalHeight = upperPowerOfTwo(height);
+		internalWidth = upperPowerOfTwo(width);
+	}
+
+	glBindTexture(GL_TEXTURE_2D, id);
+	glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, internalWidth, internalHeight, 0, internalFormat, GL_UNSIGNED_BYTE, nullptr);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+	g_system->presentBuffer();
+	glCopyTexImage2D(GL_TEXTURE_2D, 0, internalFormat, screen.left, screen.top, internalWidth, internalHeight, 0);
+}
+
+} // End of namespace Myst3
+
+#endif