OpenGL: Create video backend for GLES2, used on Raspberry Pi

CMakeLists.txt

@@ -21,6 +21,7 @@ set(BUILD_PERF OFF CACHE BOOL "Build performance profiling tool")
 set(BUILD_STATIC OFF CACHE BOOL "Build a static library")
 set(BUILD_SHARED ON CACHE BOOL "Build a shared library")
 set(BUILD_GL ON CACHE STRING "Build with OpenGL")
+set(BUILD_GLES2 OFF CACHE STRING "Build with OpenGL|ES 2")
 file(GLOB ARM_SRC ${CMAKE_SOURCE_DIR}/src/arm/*.c)
 file(GLOB GBA_SRC ${CMAKE_SOURCE_DIR}/src/gba/*.c)
 file(GLOB GBA_CHEATS_SRC ${CMAKE_SOURCE_DIR}/src/gba/cheats/*.c)
@@ -122,10 +123,11 @@ if(CMAKE_SYSTEM_NAME MATCHES .*BSD)
 else()
 	find_feature(USE_CLI_DEBUGGER "libedit")
 endif()
-if(BUILD_GL)
+if(BUILD_GL OR BUILD_GLES2)
 	find_package(OpenGL QUIET)
 	if(NOT OPENGL_FOUND)
-		set(BUILD_GL OFF)
+		set(BUILD_GL OFF CACHE BOOL "OpenGL not found" FORCE)
+		set(BUILD_GLES2 OFF CACHE BOOL "OpenGL|ES 2 not found" FORCE)
 	endif()
 endif()
 find_feature(USE_FFMPEG "libavcodec;libavformat;libavresample;libavutil;libswscale")
@@ -176,6 +178,10 @@ if(BUILD_BBB OR BUILD_RASPI OR BUILD_PANDORA)
 	endif()
 endif()
 
+if(BUILD_RASPI)
+	set(BUILD_GL OFF CACHE BOOL "OpenGL not supported" FORCE)
+endif()
+
 if(BUILD_PANDORA)
 	add_definitions(-DBUILD_PANDORA)
 endif()
@@ -398,6 +404,10 @@ if(BUILD_GL)
 	add_definitions(-DBUILD_GL)
 endif()
 
+if(BUILD_GLES2)
+	add_definitions(-DBUILD_GLES2)
+endif()
+
 if(BUILD_LIBRETRO)
 	file(GLOB RETRO_SRC ${CMAKE_SOURCE_DIR}/src/platform/libretro/*.c)
 	add_library(${BINARY_NAME}_libretro SHARED ${CORE_SRC} ${RETRO_SRC})

src/platform/opengl/gles2.c

@@ -0,0 +1,136 @@
+/* Copyright (c) 2013-2015 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "gles2.h"
+
+#include "gba/video.h"
+
+static const char* const _vertexShader =
+	"attribute vec4 position;\n"
+	"varying vec2 texCoord;\n"
+
+	"void main() {\n"
+	"	gl_Position = position;\n"
+	"	texCoord = (position.st + vec2(1.0, -1.0)) * vec2(0.46875, -0.3125);\n"
+	"}";
+
+static const char* const _fragmentShader =
+	"varying vec2 texCoord;\n"
+	"uniform sampler2D tex;\n"
+
+	"void main() {\n"
+	"	vec4 color = texture2D(tex, texCoord);\n"
+	"	color.a = 1.;\n"
+	"	gl_FragColor = color;"
+	"}";
+
+static const GLfloat _vertices[] = {
+	-1.f, -1.f,
+	-1.f, 1.f,
+	1.f, 1.f,
+	1.f, -1.f,
+};
+
+static void GBAGLES2ContextInit(struct VideoBackend* v, WHandle handle) {
+	UNUSED(handle);
+	struct GBAGLES2Context* context = (struct GBAGLES2Context*) v;
+	glGenTextures(1, &context->tex);
+	glBindTexture(GL_TEXTURE_2D, context->tex);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+#ifdef COLOR_16_BIT
+#ifdef COLOR_5_6_5
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, 0);
+#else
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_SHORT_1_5_5_5_REV, 0);
+#endif
+#else
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
+#endif
+
+	glShaderSource(context->fragmentShader, 1, (const GLchar**) &_fragmentShader, 0);
+	glShaderSource(context->vertexShader, 1, (const GLchar**) &_vertexShader, 0);
+	glAttachShader(context->program, context->vertexShader);
+	glAttachShader(context->program, context->fragmentShader);
+	char log[1024];
+	glCompileShader(context->fragmentShader);
+	glCompileShader(context->vertexShader);
+	glGetShaderInfoLog(context->fragmentShader, 1024, 0, log);
+	glGetShaderInfoLog(context->vertexShader, 1024, 0, log);
+	glLinkProgram(context->program);
+	glGetProgramInfoLog(context->program, 1024, 0, log);
+	printf("%s\n", log);
+	context->texLocation = glGetUniformLocation(context->program, "tex");
+	context->positionLocation = glGetAttribLocation(context->program, "position");
+	glClearColor(0.f, 0.f, 0.f, 1.f);
+}
+
+static void GBAGLES2ContextDeinit(struct VideoBackend* v) {
+	struct GBAGLES2Context* context = (struct GBAGLES2Context*) v;
+	glDeleteTextures(1, &context->tex);
+}
+
+static void GBAGLES2ContextResized(struct VideoBackend* v, int w, int h) {
+	int drawW = w;
+	int drawH = h;
+	if (v->lockAspectRatio) {
+		if (w * 2 > h * 3) {
+			drawW = h * 3 / 2;
+		} else if (w * 2 < h * 3) {
+			drawH = w * 2 / 3;
+		}
+	}
+	glViewport(0, 0, 240, 160);
+	glClearColor(0.f, 0.f, 0.f, 1.f);
+	glClear(GL_COLOR_BUFFER_BIT);
+	glViewport((w - drawW) / 2, (h - drawH) / 2, drawW, drawH);
+}
+
+static void GBAGLES2ContextClear(struct VideoBackend* v) {
+	UNUSED(v);
+	glClearColor(0.f, 0.f, 0.f, 1.f);
+	glClear(GL_COLOR_BUFFER_BIT);
+}
+
+void GBAGLES2ContextDrawFrame(struct VideoBackend* v) {
+	struct GBAGLES2Context* context = (struct GBAGLES2Context*) v;
+	glUseProgram(context->program);
+	glUniform1i(context->texLocation, 0);
+	glActiveTexture(GL_TEXTURE0);
+	glBindTexture(GL_TEXTURE_2D, context->tex);
+	glVertexAttribPointer(context->positionLocation, 2, GL_FLOAT, GL_FALSE, 0, _vertices);
+	glEnableVertexAttribArray(context->positionLocation);
+	glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+	glUseProgram(0);
+}
+
+void GBAGLES2ContextPostFrame(struct VideoBackend* v, const void* frame) {
+	struct GBAGLES2Context* context = (struct GBAGLES2Context*) v;
+	glBindTexture(GL_TEXTURE_2D, context->tex);
+#ifdef COLOR_16_BIT
+#ifdef COLOR_5_6_5
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, frame);
+#else
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_SHORT_1_5_5_5_REV, frame);
+#endif
+#else
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_BYTE, frame);
+#endif
+}
+
+void GBAGLES2ContextCreate(struct GBAGLES2Context* context) {
+	context->d.init = GBAGLES2ContextInit;
+	context->d.deinit = GBAGLES2ContextDeinit;
+	context->d.resized = GBAGLES2ContextResized;
+	context->d.swap = 0;
+	context->d.clear = GBAGLES2ContextClear;
+	context->d.postFrame = GBAGLES2ContextPostFrame;
+	context->d.drawFrame = GBAGLES2ContextDrawFrame;
+	context->d.setMessage = 0;
+	context->d.clearMessage = 0;
+}

src/platform/opengl/gles2.h

@@ -0,0 +1,27 @@
+/* Copyright (c) 2013-2015 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef GLES2_H
+#define GLES2_H
+
+#include <GLES2/gl2.h>
+
+#include "platform/video-backend.h"
+
+struct GBAGLES2Context {
+	struct VideoBackend d;
+
+	GLuint tex;
+	GLuint fragmentShader;
+	GLuint vertexShader;
+	GLuint program;
+	GLuint bufferObject;
+	GLuint texLocation;
+	GLuint positionLocation;
+};
+
+void GBAGLES2ContextCreate(struct GBAGLES2Context*);
+
+#endif

src/platform/perf-main.c

@@ -186,7 +186,7 @@ static void _GBAPerfRunloop(struct GBAThread* context, int* frames, bool quiet)
 			}
 		}
 		GBASyncWaitFrameEnd(&context->sync);
-		if (*frames == duration) {
+		if (duration > 0 && *frames == duration) {
 			_GBAPerfShutdown(0);
 		}
 		if (_dispatchExiting) {

src/platform/sdl/CMakeLists.txt

@@ -51,12 +51,14 @@ set(MAIN_SRC ${CMAKE_SOURCE_DIR}/src/platform/sdl/main.c)
 
 if(BUILD_RASPI)
 	add_definitions(-DBUILD_RASPI)
-	set(EGL_MAIN_SRC ${CMAKE_SOURCE_DIR}/src/platform/sdl/egl-sdl.c)
+	list(APPEND PLATFORM_SRC ${CMAKE_SOURCE_DIR}/src/platform/opengl/gles2.c)
-	set(EGL_LIBRARY "-lEGL -lGLESv2 -lbcm_host")
+	list(APPEND MAIN_SRC ${CMAKE_SOURCE_DIR}/src/platform/sdl/egl-sdl.c)
+	list(APPEND OPENGL_LIBRARY "-lEGL -lGLESv2 -lbcm_host")
+	set(BUILD_GLES2 ON CACHE BOOL "Using OpenGL|ES 2" FORCE)
 	set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fgnu89-inline")
-	add_executable(${BINARY_NAME}-rpi ${PLATFORM_SRC} ${MAIN_SRC} ${EGL_MAIN_SRC})
+	add_executable(${BINARY_NAME}-rpi ${PLATFORM_SRC} ${MAIN_SRC})
 	set_target_properties(${BINARY_NAME}-rpi PROPERTIES COMPILE_DEFINITIONS "${FEATURE_DEFINES}")
-	target_link_libraries(${BINARY_NAME}-rpi ${BINARY_NAME} ${PLATFORM_LIBRARY} ${EGL_LIBRARY})
+	target_link_libraries(${BINARY_NAME}-rpi ${BINARY_NAME} ${PLATFORM_LIBRARY} ${OPENGL_LIBRARY})
 	install(TARGETS ${BINARY_NAME}-rpi DESTINATION bin COMPONENT ${BINARY_NAME}-rpi)
 endif()
 

src/platform/sdl/egl-sdl.c

@@ -1,37 +1,26 @@
-/* Copyright (c) 2013-2014 Jeffrey Pfau
+/* Copyright (c) 2013-2015 Jeffrey Pfau
  *
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "main.h"
 
-static const char* _vertexShader =
+static void _sdlSwap(struct VideoBackend* context) {
-	"attribute vec4 position;\n"
+	UNUSED(context);
-	"varying vec2 texCoord;\n"
+	SDL_GL_SwapBuffers();
+}
 
-	"void main() {\n"
+static bool GBASDLGLES2Init(struct SDLSoftwareRenderer* renderer);
-	"	gl_Position = position;\n"
+static void GBASDLGLES2Runloop(struct GBAThread* context, struct SDLSoftwareRenderer* renderer);
-	"	texCoord = (position.st + vec2(1.0, -1.0)) * vec2(0.46875, -0.3125);\n"
+static void GBASDLGLES2Deinit(struct SDLSoftwareRenderer* renderer);
-	"}";
 
-static const char* _fragmentShader =
+void GBASDLGLES2Create(struct SDLSoftwareRenderer* renderer) {
-	"varying vec2 texCoord;\n"
+	renderer->init = GBASDLGLES2Init;
-	"uniform sampler2D tex;\n"
+	renderer->deinit = GBASDLGLES2Deinit;
+	renderer->runloop = GBASDLGLES2Runloop;
+}
 
-	"void main() {\n"
+bool GBASDLGLES2Init(struct SDLSoftwareRenderer* renderer) {
-	"	vec4 color = texture2D(tex, texCoord);\n"
-	"	color.a = 1.;\n"
-	"	gl_FragColor = color;"
-	"}";
-
-static const GLfloat _vertices[] = {
-	-1.f, -1.f,
-	-1.f, 1.f,
-	1.f, 1.f,
-	1.f, -1.f,
-};
-
-bool GBASDLInit(struct SDLSoftwareRenderer* renderer) {
 	bcm_host_init();
 	renderer->display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
 	int major, minor;
@@ -103,36 +92,19 @@ bool GBASDLInit(struct SDLSoftwareRenderer* renderer) {
 
 	renderer->d.outputBuffer = memalign(16, 256 * 256 * 4);
 	renderer->d.outputBufferStride = 256;
-	glGenTextures(1, &renderer->tex);
-	glBindTexture(GL_TEXTURE_2D, renderer->tex);
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
-	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
-	renderer->fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
-	renderer->vertexShader = glCreateShader(GL_VERTEX_SHADER);
-	renderer->program = glCreateProgram();
 
-	glShaderSource(renderer->fragmentShader, 1, (const GLchar**) &_fragmentShader, 0);
+	GBAGLES2ContextCreate(&renderer->gl);
-	glShaderSource(renderer->vertexShader, 1, (const GLchar**) &_vertexShader, 0);
+	renderer->gl.d.user = renderer;
-	glAttachShader(renderer->program, renderer->vertexShader);
+	renderer->gl.d.lockAspectRatio = renderer->lockAspectRatio;
-	glAttachShader(renderer->program, renderer->fragmentShader);
+	renderer->gl.d.filter = renderer->filter;
-	char log[1024];
+	renderer->gl.d.swap = _sdlSwap;
-	glCompileShader(renderer->fragmentShader);
+	renderer->gl.d.init(&renderer->gl.d, 0);
-	glCompileShader(renderer->vertexShader);
+	return true;
-	glGetShaderInfoLog(renderer->fragmentShader, 1024, 0, log);
-	glGetShaderInfoLog(renderer->vertexShader, 1024, 0, log);
-	glLinkProgram(renderer->program);
-	glGetProgramInfoLog(renderer->program, 1024, 0, log);
-	printf("%s\n", log);
-	renderer->texLocation = glGetUniformLocation(renderer->program, "tex");
-	renderer->positionLocation = glGetAttribLocation(renderer->program, "position");
-	glClearColor(1.f, 0.f, 0.f, 1.f);
 }
 
-void GBASDLRunloop(struct GBAThread* context, struct SDLSoftwareRenderer* renderer) {
+void GBASDLGLES2Runloop(struct GBAThread* context, struct SDLSoftwareRenderer* renderer) {
 	SDL_Event event;
+	struct VideoBackend* v = &renderer->gl.d;
 
 	while (context->state < THREAD_EXITING) {
 		while (SDL_PollEvent(&event)) {
@@ -140,27 +112,22 @@ void GBASDLRunloop(struct GBAThread* context, struct SDLSoftwareRenderer* render
 		}
 
 		if (GBASyncWaitFrameStart(&context->sync, context->frameskip)) {
-			glViewport(0, 0, 240, 160);
+			v->postFrame(v, renderer->d.outputBuffer);
-			glClear(GL_COLOR_BUFFER_BIT);
-			glUseProgram(renderer->program);
-			glUniform1i(renderer->texLocation, 0);
-			glActiveTexture(GL_TEXTURE0);
-			glBindTexture(GL_TEXTURE_2D, renderer->tex);
-			glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_BYTE, renderer->d.outputBuffer);
-			glVertexAttribPointer(renderer->positionLocation, 2, GL_FLOAT, GL_FALSE, 0, _vertices);
-			glEnableVertexAttribArray(renderer->positionLocation);
-			glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
-			glUseProgram(0);
-			eglSwapBuffers(renderer->display, renderer->surface);
 		}
+		v->drawFrame(v);
 		GBASyncWaitFrameEnd(&context->sync);
+		eglSwapBuffers(renderer->display, renderer->surface);
 	}
 }
 
-void GBASDLDeinit(struct SDLSoftwareRenderer* renderer) {
+void GBASDLGLES2Deinit(struct SDLSoftwareRenderer* renderer) {
+	if (renderer->gl.d.deinit) {
+		renderer->gl.d.deinit(&renderer->gl.d);
+	}
 	eglMakeCurrent(renderer->display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
 	eglDestroySurface(renderer->display, renderer->surface);
 	eglDestroyContext(renderer->display, renderer->context);
 	eglTerminate(renderer->display);
+	free(renderer->d.outputBuffer);
 	bcm_host_deinit();
 }

src/platform/sdl/main.c

@@ -86,6 +86,8 @@ int main(int argc, char** argv) {
 
 #ifdef BUILD_GL
 	GBASDLGLCreate(&renderer);
+#elif defined(BUILD_GLES2)
+	GBASDLGLES2Create(&renderer);
 #else
 	GBASDLSWCreate(&renderer);
 #endif

src/platform/sdl/main.h

@@ -20,13 +20,16 @@
 #pragma GCC diagnostic ignored "-Wunused-function"
 #pragma GCC diagnostic ignored "-Wunused-but-set-variable"
 #include <SDL/SDL.h>
-#include <GLES2/gl2.h>
 #include <EGL/egl.h>
 
 #include <bcm_host.h>
 #pragma GCC diagnostic pop
 #endif
 
+#ifdef BUILD_GLES2
+#include "platform/opengl/gles2.h"
+#endif
+
 #ifdef USE_PIXMAN
 #include <pixman.h>
 #endif
@@ -69,13 +72,7 @@ struct SDLSoftwareRenderer {
 	EGLSurface surface;
 	EGLContext context;
 	EGL_DISPMANX_WINDOW_T window;
-	GLuint tex;
+	struct GBAGLES2Context gl;
-	GLuint fragmentShader;
-	GLuint vertexShader;
-	GLuint program;
-	GLuint bufferObject;
-	GLuint texLocation;
-	GLuint positionLocation;
 #endif
 
 #ifdef BUILD_PANDORA
@@ -90,4 +87,8 @@ void GBASDLSWCreate(struct SDLSoftwareRenderer* renderer);
 #ifdef BUILD_GL
 void GBASDLGLCreate(struct SDLSoftwareRenderer* renderer);
 #endif
+
+#ifdef BUILD_GLES2
+void GBASDLGLES2Create(struct SDLSoftwareRenderer* renderer);
+#endif
 #endif