135 lines
3.4 KiB
C
135 lines
3.4 KiB
C
//========================================================================
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// Cursor animation
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// Copyright (c) Camilla Berglund <elmindreda@elmindreda.org>
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//
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// This software is provided 'as-is', without any express or implied
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// warranty. In no event will the authors be held liable for any damages
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// arising from the use of this software.
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//
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// Permission is granted to anyone to use this software for any purpose,
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// including commercial applications, and to alter it and redistribute it
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// freely, subject to the following restrictions:
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//
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// 1. The origin of this software must not be misrepresented; you must not
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// claim that you wrote the original software. If you use this software
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// in a product, an acknowledgment in the product documentation would
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// be appreciated but is not required.
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//
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// 2. Altered source versions must be plainly marked as such, and must not
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// be misrepresented as being the original software.
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//
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// 3. This notice may not be removed or altered from any source
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// distribution.
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//
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//========================================================================
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//
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// Cursor animation test.
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//
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//========================================================================
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#include <GLFW/glfw3.h>
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#include <stdlib.h>
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#include <math.h>
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#ifdef min
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#undef min
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#endif
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#ifdef max
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#undef max
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#endif
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#define SIZE 64 // cursor size (width & height)
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#define N 60 // number of frames
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unsigned char buffer[4 * SIZE * SIZE];
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static float max(float a, float b) { return a > b ? a : b; }
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static float min(float a, float b) { return a < b ? a : b; }
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static float star(int x, int y, float t)
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{
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float c = SIZE / 2.0f;
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float i = (0.25f * (float)sin(2.0f * 3.1415926f * t) + 0.75f);
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float k = SIZE * 0.046875f * i;
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float dist = (float)sqrt((x - c) * (x - c) + (y - c) * (y - c));
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float salpha = 1.0f - dist / c;
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float xalpha = (float)x == c ? c : k / (float)fabs(x - c);
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float yalpha = (float)y == c ? c : k / (float)fabs(y - c);
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return max(0.0f, min(1.0f, i * salpha * 0.2f + salpha * xalpha * yalpha));
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}
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static GLFWcursor* load_frame(float t)
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{
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int i = 0, x, y;
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const GLFWimage image = { SIZE, SIZE, buffer };
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for (y = 0; y < image.width; y++)
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{
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for (x = 0; x < image.height; x++)
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{
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buffer[i++] = 255;
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buffer[i++] = 255;
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buffer[i++] = 255;
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buffer[i++] = (unsigned char)(255 * star(x, y, t));
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}
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}
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return glfwCreateCursor(&image, image.width / 2, image.height / 2);
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}
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int main(void)
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{
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int i;
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double t0, t1, frameTime = 0.0;
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GLFWwindow* window;
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GLFWcursor* frames[N];
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if (!glfwInit())
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exit(EXIT_FAILURE);
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window = glfwCreateWindow(640, 480, "Cursor animation", NULL, NULL);
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if (!window)
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{
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glfwTerminate();
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exit(EXIT_FAILURE);
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}
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glfwMakeContextCurrent(window);
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glfwSwapInterval(1);
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for (i = 0; i < N; i++)
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frames[i] = load_frame(i / (float)N);
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i = 0;
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t0 = glfwGetTime();
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while (!glfwWindowShouldClose(window))
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{
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glClear(GL_COLOR_BUFFER_BIT);
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glfwSetCursor(window, frames[i]);
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glfwSwapBuffers(window);
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glfwPollEvents();
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t1 = glfwGetTime();
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frameTime += t1 - t0;
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t0 = t1;
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while (frameTime > 1.0 / (double)N)
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{
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i = (i + 1) % N;
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frameTime -= 1.0 / (double)N;
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}
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}
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glfwTerminate();
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exit(EXIT_SUCCESS);
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}
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