Add test with GLFW framework

experimental/GLFWTest/glfw_main.cpp

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GLFW/glfw3.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "GrContext.h"
+
+#include "SkCanvas.h"
+#include "SkImage.h"
+#include "SkRSXform.h"
+#include "SkSurface.h"
+#include "Timer.h"
+
+GrContext* sContext = nullptr;
+SkSurface* sSurface = nullptr;
+
+static void error_callback(int error, const char* description) {
+    fputs(description, stderr);
+}
+
+static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods) {
+    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
+        glfwSetWindowShouldClose(window, GL_TRUE);
+}
+
+
+static void init_skia(int w, int h) {
+    sContext = GrContext::Create(kOpenGL_GrBackend, 0);
+    
+    GrBackendRenderTargetDesc desc;
+    desc.fWidth = w;
+    desc.fHeight = h;
+    desc.fConfig = kSkia8888_GrPixelConfig;
+    desc.fOrigin = kBottomLeft_GrSurfaceOrigin;
+    desc.fSampleCnt = 1;
+    desc.fStencilBits = 0;
+    desc.fRenderTargetHandle = 0;  // assume default framebuffer
+ 
+    sSurface = SkSurface::NewFromBackendRenderTarget(sContext, desc, NULL);
+}
+
+static void cleanup_skia() {
+    delete sSurface;
+    delete sContext;
+}
+
+const int kGrid = 100;
+const int kWidth = 960;
+const int kHeight = 640;
+
+int main(void) {
+    GLFWwindow* window;
+    glfwSetErrorCallback(error_callback);
+    if (!glfwInit()) {
+        exit(EXIT_FAILURE);
+    }
+    
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
+    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
+    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+    glfwWindowHint(GLFW_SRGB_CAPABLE, GL_TRUE);
+    
+    window = glfwCreateWindow(kWidth, kHeight, "Simple example", NULL, NULL);
+    if (!window) {
+        glfwTerminate();
+        exit(EXIT_FAILURE);
+    }
+    glfwMakeContextCurrent(window);
+    
+    init_skia(kWidth, kHeight);
+    
+    SkAutoTUnref<SkImage> atlas;
+    SkRSXform   xform[kGrid*kGrid+1];
+    SkRect      tex[kGrid*kGrid+1];
+    WallTimer   timer;
+    float       times[32];
+    int         currentTime;
+
+    SkAutoTUnref<SkData> imageData(SkData::NewFromFileName("ship.png"));
+    atlas.reset(SkImage::NewFromEncoded(imageData));
+    if (!atlas) {
+        SkDebugf("\nCould not decode file ship.png\n");
+        
+        cleanup_skia();
+        glfwDestroyWindow(window);
+        glfwTerminate();
+        exit(EXIT_FAILURE);
+    }
+    
+    SkScalar anchorX = atlas->width()*0.5f;
+    SkScalar anchorY = atlas->height()*0.5f;
+    int currIndex = 0;
+    for (int x = 0; x < kGrid; x++) {
+        for (int y = 0; y < kGrid; y++) {
+            float xPos = (x / (kGrid - 1.0)) * kWidth;
+            float yPos = (y / (kGrid - 1.0)) * kWidth;
+            
+            tex[currIndex] = SkRect::MakeLTRB(0.0f, 0.0f, atlas->width(), atlas->height());
+            xform[currIndex] = SkRSXform::MakeFromRadians(2.0f, SK_ScalarPI*0.5f,
+                                                          xPos, yPos, anchorX, anchorY);
+            currIndex++;
+        }
+    }
+    tex[currIndex] = SkRect::MakeLTRB(0.0f, 0.0f, atlas->width(), atlas->height());
+    xform[currIndex] = SkRSXform::MakeFromRadians(2.0f, SK_ScalarPI*0.5f,
+                                                  kWidth*0.5f, kHeight*0.5f, anchorX, anchorY);
+    
+    currentTime = 0;
+    
+    glfwSwapInterval(1);
+    glfwSetKeyCallback(window, key_callback);
+    
+    // Draw to the surface via its SkCanvas.
+    SkCanvas* canvas = sSurface->getCanvas();   // We don't manage this pointer's lifetime.
+    SkPaint paint;
+    paint.setFilterQuality(kLow_SkFilterQuality);
+    paint.setColor(SK_ColorWHITE);
+    paint.setTextSize(15.0f);
+
+    while (!glfwWindowShouldClose(window)) {
+        const float kCosDiff = 0.99984769515f;
+        const float kSinDiff = 0.01745240643f;
+
+        timer.start();
+        
+        glfwPollEvents();
+        
+        float meanTime = 0.0f;
+        for (int i = 0; i < 32; ++i) {
+            meanTime += times[i];
+        }
+        meanTime /= 32.f;
+        char outString[64];
+        float fps = 1000.f/meanTime;
+        sprintf(outString, "fps: %f ms: %f", fps, meanTime);
+        
+        for (int i = 0; i < kGrid*kGrid+1; ++i) {
+            SkScalar c = xform[i].fSCos;
+            SkScalar s = xform[i].fSSin;
+        
+            SkScalar dx = c*anchorX - s*anchorY;
+            SkScalar dy = s*anchorX + c*anchorY;
+
+            xform[i].fSCos = kCosDiff*c - kSinDiff*s;
+            xform[i].fSSin = kSinDiff*c + kCosDiff*s;
+            
+            dx -= xform[i].fSCos*anchorX - xform[i].fSSin*anchorY;
+            dy -= xform[i].fSSin*anchorX + xform[i].fSCos*anchorY;
+            xform[i].fTx += dx;
+            xform[i].fTy += dy;
+        }
+        
+        canvas->clear(SK_ColorBLACK);
+        canvas->drawAtlas(atlas, xform, tex, nullptr, kGrid*kGrid+1, SkXfermode::kSrcOver_Mode,
+                          nullptr, &paint);
+        canvas->drawText(outString, strlen(outString), 100.f, 100.f, paint);
+        
+        canvas->flush();
+        
+        timer.end();
+        times[currentTime] = (float)(timer.fWall);
+        currentTime = (currentTime + 1) & 0x1f;
+        
+        glfwSwapBuffers(window);
+    }
+  
+    cleanup_skia();
+    
+    glfwDestroyWindow(window);
+    glfwTerminate();
+    exit(EXIT_SUCCESS);
+}