skia2/experimental/GLFWTest/glfw_main.cpp

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/*
* 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::MakeFromBackendRenderTarget(sContext, desc, nullptr, nullptr).release();
}
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);
sk_sp<SkImage> atlas;
SkRSXform xform[kGrid*kGrid+1];
SkRect tex[kGrid*kGrid+1];
WallTimer timer;
float times[32];
int currentTime;
sk_sp<SkData> imageData(SkData::MakeFromFileName("ship.png"));
atlas.reset(SkImage::NewFromEncoded(imageData.get()));
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);
}