1/* 2 * Copyright 2015 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 * 7 */ 8 9#include "GrBackendSurface.h" 10#include "GrContext.h" 11#include "SDL.h" 12#include "SkCanvas.h" 13#include "SkRandom.h" 14#include "SkSurface.h" 15 16#include "gl/GrGLInterface.h" 17#include "gl/GrGLUtil.h" 18 19#if defined(SK_BUILD_FOR_ANDROID) 20#include <GLES/gl.h> 21#elif defined(SK_BUILD_FOR_UNIX) 22#include <GL/gl.h> 23#elif defined(SK_BUILD_FOR_MAC) 24#include <OpenGL/gl.h> 25#elif defined(SK_BUILD_FOR_IOS) 26#include <OpenGLES/ES2/gl.h> 27#endif 28 29/* 30 * This application is a simple example of how to combine SDL and Skia it demonstrates: 31 * how to setup gpu rendering to the main window 32 * how to perform cpu-side rendering and draw the result to the gpu-backed screen 33 * draw simple primitives (rectangles) 34 * draw more complex primitives (star) 35 */ 36 37struct ApplicationState { 38 ApplicationState() : fQuit(false) {} 39 // Storage for the user created rectangles. The last one may still be being edited. 40 SkTArray<SkRect> fRects; 41 bool fQuit; 42}; 43 44static void handle_error() { 45 const char* error = SDL_GetError(); 46 SkDebugf("SDL Error: %s\n", error); 47 SDL_ClearError(); 48} 49 50static void handle_events(ApplicationState* state, SkCanvas* canvas) { 51 SDL_Event event; 52 while(SDL_PollEvent(&event)) { 53 switch (event.type) { 54 case SDL_MOUSEMOTION: 55 if (event.motion.state == SDL_PRESSED) { 56 SkRect& rect = state->fRects.back(); 57 rect.fRight = event.motion.x; 58 rect.fBottom = event.motion.y; 59 } 60 break; 61 case SDL_MOUSEBUTTONDOWN: 62 if (event.button.state == SDL_PRESSED) { 63 state->fRects.push_back() = SkRect::MakeLTRB(SkIntToScalar(event.button.x), 64 SkIntToScalar(event.button.y), 65 SkIntToScalar(event.button.x), 66 SkIntToScalar(event.button.y)); 67 } 68 break; 69 case SDL_KEYDOWN: { 70 SDL_Keycode key = event.key.keysym.sym; 71 if (key == SDLK_ESCAPE) { 72 state->fQuit = true; 73 } 74 break; 75 } 76 case SDL_QUIT: 77 state->fQuit = true; 78 break; 79 default: 80 break; 81 } 82 } 83} 84 85// Creates a star type shape using a SkPath 86static SkPath create_star() { 87 static const int kNumPoints = 5; 88 SkPath concavePath; 89 SkPoint points[kNumPoints] = {{0, SkIntToScalar(-50)} }; 90 SkMatrix rot; 91 rot.setRotate(SkIntToScalar(360) / kNumPoints); 92 for (int i = 1; i < kNumPoints; ++i) { 93 rot.mapPoints(points + i, points + i - 1, 1); 94 } 95 concavePath.moveTo(points[0]); 96 for (int i = 0; i < kNumPoints; ++i) { 97 concavePath.lineTo(points[(2 * i) % kNumPoints]); 98 } 99 concavePath.setFillType(SkPath::kEvenOdd_FillType); 100 SkASSERT(!concavePath.isConvex()); 101 concavePath.close(); 102 return concavePath; 103} 104 105#if defined(SK_BUILD_FOR_ANDROID) 106int SDL_main(int argc, char** argv) { 107#else 108int main(int argc, char** argv) { 109#endif 110 uint32_t windowFlags = 0; 111 112 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3); 113 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0); 114 115 SDL_GLContext glContext = nullptr; 116#if defined(SK_BUILD_FOR_ANDROID) || defined(SK_BUILD_FOR_IOS) 117 // For Android/iOS we need to set up for OpenGL ES and we make the window hi res & full screen 118 SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES); 119 windowFlags = SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | 120 SDL_WINDOW_BORDERLESS | SDL_WINDOW_FULLSCREEN_DESKTOP | 121 SDL_WINDOW_ALLOW_HIGHDPI; 122#else 123 // For all other clients we use the core profile and operate in a window 124 SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE); 125 126 windowFlags = SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE; 127#endif 128 static const int kStencilBits = 8; // Skia needs 8 stencil bits 129 SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8); 130 SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8); 131 SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8); 132 SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1); 133 SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 0); 134 SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, kStencilBits); 135 136 SDL_GL_SetAttribute(SDL_GL_ACCELERATED_VISUAL, 1); 137 138 // If you want multisampling, uncomment the below lines and set a sample count 139 static const int kMsaaSampleCount = 0; //4; 140 // SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1); 141 // SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, kMsaaSampleCount); 142 143 /* 144 * In a real application you might want to initialize more subsystems 145 */ 146 if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS) != 0) { 147 handle_error(); 148 return 1; 149 } 150 151 // Setup window 152 // This code will create a window with the same resolution as the user's desktop. 153 SDL_DisplayMode dm; 154 if (SDL_GetDesktopDisplayMode(0, &dm) != 0) { 155 handle_error(); 156 return 1; 157 } 158 159 SDL_Window* window = SDL_CreateWindow("SDL Window", SDL_WINDOWPOS_CENTERED, 160 SDL_WINDOWPOS_CENTERED, dm.w, dm.h, windowFlags); 161 162 if (!window) { 163 handle_error(); 164 return 1; 165 } 166 167 // To go fullscreen 168 // SDL_SetWindowFullscreen(window, SDL_WINDOW_FULLSCREEN); 169 170 // try and setup a GL context 171 glContext = SDL_GL_CreateContext(window); 172 if (!glContext) { 173 handle_error(); 174 return 1; 175 } 176 177 int success = SDL_GL_MakeCurrent(window, glContext); 178 if (success != 0) { 179 handle_error(); 180 return success; 181 } 182 183 uint32_t windowFormat = SDL_GetWindowPixelFormat(window); 184 int contextType; 185 SDL_GL_GetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, &contextType); 186 187 188 int dw, dh; 189 SDL_GL_GetDrawableSize(window, &dw, &dh); 190 191 glViewport(0, 0, dw, dh); 192 glClearColor(1, 1, 1, 1); 193 glClearStencil(0); 194 glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); 195 196 // setup GrContext 197 auto interface = GrGLMakeNativeInterface(); 198 199 // setup contexts 200 sk_sp<GrContext> grContext(GrContext::MakeGL(interface)); 201 SkASSERT(grContext); 202 203 // Wrap the frame buffer object attached to the screen in a Skia render target so Skia can 204 // render to it 205 GrGLint buffer; 206 GR_GL_GetIntegerv(interface.get(), GR_GL_FRAMEBUFFER_BINDING, &buffer); 207 GrGLFramebufferInfo info; 208 info.fFBOID = (GrGLuint) buffer; 209 SkColorType colorType; 210 211 if (SDL_PIXELFORMAT_RGBA8888 == windowFormat) { 212 info.fFormat = GR_GL_RGBA8; 213 colorType = kRGBA_8888_SkColorType; 214 } else { 215 SkASSERT(SDL_PIXELFORMAT_BGRA8888); 216 colorType = kBGRA_8888_SkColorType; 217 if (SDL_GL_CONTEXT_PROFILE_ES == contextType) { 218 info.fFormat = GR_GL_BGRA8; 219 } else { 220 // We assume the internal format is RGBA8 on desktop GL 221 info.fFormat = GR_GL_RGBA8; 222 } 223 } 224 225 GrBackendRenderTarget target(dw, dh, kMsaaSampleCount, kStencilBits, info); 226 227 // setup SkSurface 228 // To use distance field text, use commented out SkSurfaceProps instead 229 // SkSurfaceProps props(SkSurfaceProps::kUseDeviceIndependentFonts_Flag, 230 // SkSurfaceProps::kLegacyFontHost_InitType); 231 SkSurfaceProps props(SkSurfaceProps::kLegacyFontHost_InitType); 232 233 sk_sp<SkSurface> surface(SkSurface::MakeFromBackendRenderTarget(grContext.get(), target, 234 kBottomLeft_GrSurfaceOrigin, 235 colorType, nullptr, &props)); 236 237 SkCanvas* canvas = surface->getCanvas(); 238 canvas->scale((float)dw/dm.w, (float)dh/dm.h); 239 240 ApplicationState state; 241 242 const char* helpMessage = "Click and drag to create rects. Press esc to quit."; 243 244 SkPaint paint; 245 246 // create a surface for CPU rasterization 247 sk_sp<SkSurface> cpuSurface(SkSurface::MakeRaster(canvas->imageInfo())); 248 249 SkCanvas* offscreen = cpuSurface->getCanvas(); 250 offscreen->save(); 251 offscreen->translate(50.0f, 50.0f); 252 offscreen->drawPath(create_star(), paint); 253 offscreen->restore(); 254 255 sk_sp<SkImage> image = cpuSurface->makeImageSnapshot(); 256 257 int rotation = 0; 258 while (!state.fQuit) { // Our application loop 259 SkRandom rand; 260 canvas->clear(SK_ColorWHITE); 261 handle_events(&state, canvas); 262 263 paint.setColor(SK_ColorBLACK); 264 canvas->drawText(helpMessage, strlen(helpMessage), SkIntToScalar(100), 265 SkIntToScalar(100), paint); 266 for (int i = 0; i < state.fRects.count(); i++) { 267 paint.setColor(rand.nextU() | 0x44808080); 268 canvas->drawRect(state.fRects[i], paint); 269 } 270 271 // draw offscreen canvas 272 canvas->save(); 273 canvas->translate(dm.w / 2.0, dm.h / 2.0); 274 canvas->rotate(rotation++); 275 canvas->drawImage(image, -50.0f, -50.0f); 276 canvas->restore(); 277 278 canvas->flush(); 279 SDL_GL_SwapWindow(window); 280 } 281 282 if (glContext) { 283 SDL_GL_DeleteContext(glContext); 284 } 285 286 //Destroy window 287 SDL_DestroyWindow(window); 288 289 //Quit SDL subsystems 290 SDL_Quit(); 291 return 0; 292} 293