Initial commit

graphics/opengl/context.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/>.
+ *
+ */
+
+#define GLAD_GL_IMPLEMENTATION
+// sscanf_s is used by glad on MSVC only
+// we can't know before config.h is loaded that GLAD will be used
+// but at this time it will be too late to allow sscanf_s
+#ifdef _MSC_VER
+#define FORBIDDEN_SYMBOL_EXCEPTION_sscanf_s
+#endif
+
+#include "graphics/opengl/context.h"
+
+#include "common/debug.h"
+#include "common/str.h"
+#include "common/system.h"
+#include "common/textconsole.h"
+#include "common/tokenizer.h"
+
+#include "graphics/opengl/system_headers.h"
+
+#if defined(USE_OPENGL)
+
+#ifdef USE_GLAD
+static GLADapiproc loadFunc(const char *name) {
+	return (GLADapiproc)g_system->getOpenGLProcAddress(name);
+}
+#endif
+
+namespace Common {
+DECLARE_SINGLETON(OpenGL::Context);
+}
+
+namespace OpenGL {
+
+Context::Context() {
+	reset();
+}
+
+void Context::reset() {
+	type = kContextNone;
+	maxTextureSize = 0;
+
+	majorVersion = 0;
+	minorVersion = 0;
+	glslVersion = 0;
+
+	NPOTSupported = false;
+	imagingSupported = false;
+	shadersSupported = false;
+	enginesShadersSupported = false;
+	multitextureSupported = false;
+	framebufferObjectSupported = false;
+	framebufferObjectMultisampleSupported = false;
+	multisampleMaxSamples = -1;
+	bgraSupported = false;
+	packedPixelsSupported = false;
+	packedDepthStencilSupported = false;
+	unpackSubImageSupported = false;
+	OESDepth24 = false;
+	textureEdgeClampSupported = false;
+	textureBorderClampSupported = false;
+	textureMirrorRepeatSupported = false;
+	textureMaxLevelSupported = false;
+	textureLookupPrecision = 0;
+}
+
+void Context::initialize(ContextType contextType) {
+	// Initialize default state.
+	reset();
+	if (contextType == kContextNone) {
+		return;
+	}
+
+	type = contextType;
+
+#ifdef USE_GLAD
+	int gladVersion;
+	switch (type) {
+	case kContextGL:
+		gladVersion = gladLoadGL(loadFunc);
+		break;
+
+	case kContextGLES:
+		gladVersion = gladLoadGLES1(loadFunc);
+		break;
+
+	case kContextGLES2:
+		gladVersion = gladLoadGLES2(loadFunc);
+		break;
+
+	default:
+		gladVersion = 0;
+		break;
+	}
+
+	majorVersion = GLAD_VERSION_MAJOR(gladVersion);
+	minorVersion = GLAD_VERSION_MINOR(gladVersion);
+
+	if (!gladVersion) {
+		// If gladVersion is 0 it means that loading failed and glad didn't set up anything
+		error("Couldn't initialize OpenGL");
+	}
+#else
+	const char *verString = (const char *)glGetString(GL_VERSION);
+	if (!verString) {
+		majorVersion = minorVersion = 0;
+		int errorCode = glGetError();
+		warning("Could not fetch GL_VERSION: %d", errorCode);
+		return;
+	} else if (type == kContextGL) {
+		// OpenGL version number is either of the form major.minor or major.minor.release,
+		// where the numbers all have one or more digits
+		if (sscanf(verString, "%d.%d", &majorVersion, &minorVersion) != 2) {
+			majorVersion = minorVersion = 0;
+			warning("Could not parse GL version '%s'", verString);
+		}
+	} else if (type == kContextGLES) {
+		// The form of the string is "OpenGL ES-<profile> <major>.<minor>",
+		// where <profile> is either "CM" (Common) or "CL" (Common-Lite),
+		// and <major> and <minor> are integers.
+		char profile[3];
+		if (sscanf(verString, "OpenGL ES-%2s %d.%d", profile,
+					&majorVersion, &minorVersion) != 3) {
+			majorVersion = minorVersion = 0;
+			warning("Could not parse GL ES version '%s'", verString);
+		}
+	} else if (type == kContextGLES2) {
+		// The version is of the form
+		// OpenGL<space>ES<space><version number><space><vendor-specific information>
+		// version number format is not defined
+		// There is only OpenGL ES 2.0 anyway
+		if (sscanf(verString, "OpenGL ES %d.%d", &majorVersion, &minorVersion) != 2) {
+			minorVersion = 0;
+			if (sscanf(verString, "OpenGL ES %d ", &majorVersion) != 1) {
+				majorVersion = 0;
+				warning("Could not parse GL ES 2 version '%s'", verString);
+			}
+		}
+	}
+#endif
+
+	glslVersion = getGLSLVersion();
+
+	// Obtain maximum texture size.
+	glGetIntegerv(GL_MAX_TEXTURE_SIZE, (GLint *)&maxTextureSize);
+
+	const char *extString = (const char *)glGetString(GL_EXTENSIONS);
+	if (!extString) {
+		extString = "";
+	}
+
+	bool EXTFramebufferMultisample = false;
+	bool EXTFramebufferBlit = false;
+
+	Common::StringTokenizer tokenizer(extString, " ");
+	while (!tokenizer.empty()) {
+		Common::String token = tokenizer.nextToken();
+
+		if (token == "GL_ARB_texture_non_power_of_two" || token == "GL_OES_texture_npot") {
+			NPOTSupported = true;
+		} else if (token == "GL_ARB_imaging") {
+			imagingSupported = true;
+		} else if (token == "GL_ARB_multitexture") {
+			multitextureSupported = true;
+		} else if (token == "GL_ARB_framebuffer_object") {
+			framebufferObjectSupported = true;
+		} else if (token == "GL_EXT_bgra" || token == "GL_EXT_texture_format_BGRA8888") {
+			bgraSupported = true;
+		} else if (token == "GL_EXT_packed_pixels" || token == "GL_APPLE_packed_pixels") {
+			packedPixelsSupported = true;
+		} else if (token == "GL_EXT_packed_depth_stencil" || token == "GL_OES_packed_depth_stencil") {
+			packedDepthStencilSupported = true;
+		} else if (token == "GL_EXT_unpack_subimage") {
+			unpackSubImageSupported = true;
+		} else if (token == "GL_EXT_framebuffer_multisample") {
+			EXTFramebufferMultisample = true;
+		} else if (token == "GL_EXT_framebuffer_blit") {
+			EXTFramebufferBlit = true;
+		} else if (token == "GL_OES_depth24") {
+			OESDepth24 = true;
+		} else if (token == "GL_SGIS_texture_edge_clamp") {
+			textureEdgeClampSupported = true;
+		} else if (token == "GL_ARB_texture_border_clamp" || token == "GL_SGIS_texture_border_clamp" || token == "GL_OES_texture_border_clamp" ||
+		           token == "GL_EXT_texture_border_clamp" || token == "GL_NV_texture_border_clamp") {
+			textureBorderClampSupported = true;
+		} else if (token == "GL_ARB_texture_mirrored_repeat" || token == "GL_OES_texture_mirrored_repeat" || token == "GL_IBM_texture_mirrored_repeat") {
+			textureMirrorRepeatSupported = true;
+		} else if (token == "GL_SGIS_texture_lod" || token == "GL_APPLE_texture_max_level") {
+			textureMaxLevelSupported = true;
+		}
+	}
+
+	if (type == kContextGLES2) {
+// OGLES2 on AmigaOS reports GLSL version as 0.9 but we do what is needed to make it work
+// so let's pretend it supports 1.00
+#if defined(__amigaos4__)
+		if (glslVersion < 100) {
+			glslVersion = 100;
+		}
+#endif
+		// GLES2 always has (limited) NPOT support.
+		NPOTSupported = true;
+
+		// GLES2 always has imaging support
+		imagingSupported = true;
+
+		// GLES2 always has shader support.
+		shadersSupported = true;
+		// GLES2 should always have GLSL ES 1.00 support but let's make sure
+		enginesShadersSupported = (glslVersion >= 100);
+
+		// GLES2 always has multi texture support.
+		multitextureSupported = true;
+
+		// GLES2 always has FBO support.
+		framebufferObjectSupported = true;
+
+		packedPixelsSupported = true;
+		textureEdgeClampSupported = true;
+		textureMirrorRepeatSupported = true;
+
+		// OpenGL ES 3.0 and later adds multisample FBOs, and always has the following extensions
+		if (isGLVersionOrHigher(3, 0)) {
+			framebufferObjectMultisampleSupported = true;
+			packedDepthStencilSupported = true;
+			textureMaxLevelSupported = true;
+			unpackSubImageSupported = true;
+			OESDepth24 = true;
+		}
+		// OpenGL ES 3.2 and later always has texture border clamp support
+		if (isGLVersionOrHigher(3, 2)) {
+			textureBorderClampSupported = true;
+		}
+
+		// In GLES2, texture lookup is done using lowp (and mediump is not always available)
+		GLint range[2];
+		GLint precision = 0;
+		glGetShaderPrecisionFormat(GL_FRAGMENT_SHADER, GL_LOW_FLOAT, range, &precision);
+		textureLookupPrecision = precision;
+
+		debug(5, "OpenGL: GLES2 context initialized");
+	} else if (type == kContextGLES) {
+		// GLES doesn't support shaders natively
+
+		// ScummVM does not support multisample FBOs with GLES for now
+		framebufferObjectMultisampleSupported = false;
+
+		// GLES always has imaging support
+		imagingSupported = true;
+
+		packedPixelsSupported = true;
+		textureEdgeClampSupported = true;
+		// No border clamping in GLES
+		// No mirror repeat in GLES
+		// Precision is irrelevant (shaders) in GLES
+
+		debug(5, "OpenGL: GLES context initialized");
+	} else if (type == kContextGL) {
+		// Official support of shaders starts with version 110
+		// Older versions didn't support the #version directive and were only available through
+		// ARB extensions which we removed support for
+		shadersSupported = glslVersion >= 110;
+
+		// In GL mode engines need GLSL 1.20
+		enginesShadersSupported = glslVersion >= 120;
+
+		// Desktop GL always has unpack sub-image support
+		unpackSubImageSupported = true;
+
+		framebufferObjectMultisampleSupported = EXTFramebufferMultisample && EXTFramebufferBlit;
+
+		// OpenGL 1.2 and later always has packed pixels, texture edge clamp and texture max level support
+		if (isGLVersionOrHigher(1, 2)) {
+			bgraSupported = true;
+			packedPixelsSupported = true;
+			textureEdgeClampSupported = true;
+			textureMaxLevelSupported = true;
+		}
+		// OpenGL 1.3 adds texture border clamp support and mandatory imaging support
+		if (isGLVersionOrHigher(1, 3)) {
+			imagingSupported = true;
+			textureBorderClampSupported = true;
+		}
+		// OpenGL 1.4 adds texture mirror repeat support
+		if (isGLVersionOrHigher(1, 4)) {
+			textureMirrorRepeatSupported = true;
+		}
+
+		// In OpenGL precision is always enough
+		textureLookupPrecision = UINT_MAX;
+
+		debug(5, "OpenGL: GL context initialized");
+	} else {
+		warning("OpenGL: Unknown context initialized");
+	}
+
+	if (framebufferObjectMultisampleSupported) {
+		glGetIntegerv(GL_MAX_SAMPLES, (GLint *)&multisampleMaxSamples);
+	}
+
+	const char *glslVersionString = glslVersion ? (const char *)glGetString(GL_SHADING_LANGUAGE_VERSION) : "";
+
+	// Log features supported by GL context.
+	debug(5, "OpenGL version: %s", glGetString(GL_VERSION));
+	debug(5, "OpenGL vendor: %s", glGetString(GL_VENDOR));
+	debug(5, "OpenGL renderer: %s", glGetString(GL_RENDERER));
+	debug(5, "OpenGL: version %d.%d", majorVersion, minorVersion);
+	debug(5, "OpenGL: GLSL version string: %s", glslVersionString ? glslVersionString : "<none>");
+	debug(5, "OpenGL: GLSL version: %d", glslVersion);
+	debug(5, "OpenGL: Max texture size: %d", maxTextureSize);
+	debug(5, "OpenGL: NPOT texture support: %d", NPOTSupported);
+	debug(5, "OpenGL: Imaging support: %d", imagingSupported);
+	debug(5, "OpenGL: Shader support: %d", shadersSupported);
+	debug(5, "OpenGL: Shader support for engines: %d", enginesShadersSupported);
+	debug(5, "OpenGL: Multitexture support: %d", multitextureSupported);
+	debug(5, "OpenGL: FBO support: %d", framebufferObjectSupported);
+	debug(5, "OpenGL: Multisample FBO support: %d", framebufferObjectMultisampleSupported);
+	debug(5, "OpenGL: Multisample max number: %d", multisampleMaxSamples);
+	debug(5, "OpenGL: BGRA support: %d", bgraSupported);
+	debug(5, "OpenGL: Packed pixels support: %d", packedPixelsSupported);
+	debug(5, "OpenGL: Packed depth stencil support: %d", packedDepthStencilSupported);
+	debug(5, "OpenGL: Unpack subimage support: %d", unpackSubImageSupported);
+	debug(5, "OpenGL: OpenGL ES depth 24 support: %d", OESDepth24);
+	debug(5, "OpenGL: Texture edge clamping support: %d", textureEdgeClampSupported);
+	debug(5, "OpenGL: Texture border clamping support: %d", textureBorderClampSupported);
+	debug(5, "OpenGL: Texture mirror repeat support: %d", textureMirrorRepeatSupported);
+	debug(5, "OpenGL: Texture max level support: %d", textureMaxLevelSupported);
+	debug(5, "OpenGL: Texture lookup precision: %d", textureLookupPrecision);
+}
+
+int Context::getGLSLVersion() const {
+#if USE_FORCED_GLES
+	return 0;
+#else
+	// No shader support in GLES
+	if (type == kContextGLES) {
+		return 0;
+	}
+
+	// No shader support in OpenGL 1.x
+	if (type == kContextGL && !isGLVersionOrHigher(2, 0)) {
+		return 0;
+	}
+
+	const char *glslVersionString = (const char *)glGetString(GL_SHADING_LANGUAGE_VERSION);
+	if (!glslVersionString) {
+		warning("Could not get GLSL version");
+		return 0;
+	}
+
+	// Search for the first digit in the version string and parse from there
+	const char *glslVersionStringNum;
+	for (glslVersionStringNum = glslVersionString; *glslVersionStringNum != '\0'; glslVersionStringNum++) {
+		if (*glslVersionStringNum >= '0' &&
+		    *glslVersionStringNum <= '9') {
+			break;
+		}
+	}
+
+	// Here *glslVersionStringNum is either a digit or a NUL character
+
+	int glslMajorVersion, glslMinorVersion;
+	if (sscanf(glslVersionStringNum, "%d.%d", &glslMajorVersion, &glslMinorVersion) != 2) {
+		warning("Could not parse GLSL version '%s' extracted from '%s'", glslVersionStringNum, glslVersionString);
+		return 0;
+	}
+
+	return glslMajorVersion * 100 + glslMinorVersion;
+#endif
+}
+
+} // End of namespace OpenGL
+
+#endif