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绘制openCV logo，实现只转一次之后保持不动的效果 #30

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绘制openCV logo，实现只转一次之后保持不动的效果 #30

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56 changes: 55 additions & 1 deletion src/main.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,59 @@ static void render() {
/* CHECK_GL(glEnd()); */
}


static void renderRing(float x, float y, float radius, float inner_radius, float r, float g, float b, int start, int end) {
constexpr int n = 3600;
constexpr float pi = 3.1415926535897f;
start *= 10;
end *= 10;

static int cnt = 0;
static int ok = 0;
if (ok) {
cnt = n;
}
else {
cnt += 10;
if (cnt > n) {
cnt -= n;
ok += 1;
}
}

for (int i = 0; i <= cnt; i++) {
if (start <= end) {
if (i > start && i <= end) continue;
}
else {
if (i > start || i <= end) continue;
}
float angel = i / (float)n * pi * 2;
float angel_next = (i + 1) / (float)n * pi * 2;
glColor3f(r, g, b);
glVertex3f(radius * sinf(angel) + x, radius * cosf(angel) + y, 0.0f);
glVertex3f(radius * sinf(angel_next) + x, radius * cosf(angel_next) + y, 0.0f);
glVertex3f(inner_radius * sinf(angel) + x, inner_radius * cosf(angel) + y, 0.0f);

glVertex3f(inner_radius * sinf(angel) + x, inner_radius * cosf(angel) + y, 0.0f);
glVertex3f(inner_radius * sinf(angel_next) + x, inner_radius * cosf(angel_next) + y, 0.0f);
glVertex3f(radius * sinf(angel_next) + x, radius * cosf(angel_next) + y, 0.0f);
}
}

static void renderCVLogo() {
glBegin(GL_TRIANGLES);
float r = 0.4f;
float r_in = 0.4f * r;

constexpr float sq = 0.43301270189f;

renderRing(-sq, -0.25f, r, r_in, 0.0f, 1.0f, 0.0f, 30, 90);
renderRing(sq, -0.25f, r, r_in, 0.0f, 0.0f, 1.0f, 330, 30);
renderRing(0.0f, 0.5f, r, r_in, 1.0f, 0.0f, 0.0f, 150, 210);
CHECK_GL(glEnd());
}

int main() {
if (!glfwInit()) {
const char *errmsg;
Expand Down Expand Up @@ -108,7 +161,8 @@ int main() {
while (!glfwWindowShouldClose(window)) {
// render graphics
CHECK_GL(glClear(GL_COLOR_BUFFER_BIT));
render();
//render();
renderCVLogo();
// refresh screen
glfwSwapBuffers(window);
glfwPollEvents();
Expand Down