7 #define HSV_WHEEL_SIZE 128
11 void draw_hsv_wheel(float y, float rad, float theta, float value)
15 glActiveTexture(GL_TEXTURE0);
17 glEnable(GL_TEXTURE_2D);
19 glBindTexture(GL_TEXTURE_2D, hsv_wheel_num);
21 glActiveTexture(GL_TEXTURE1);
23 glBindTexture(GL_TEXTURE_2D, 0);
25 glActiveTexture(GL_TEXTURE0);
28 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
34 glTexCoord2f(0.0f, 1.0f);
37 glTexCoord2f(1.0f, 1.0f);
38 glVertex2f(0.2f * 9.0f / 16.0f, y);
40 glTexCoord2f(1.0f, 0.0f);
41 glVertex2f(0.2f * 9.0f / 16.0f, y + 0.2f);
43 glTexCoord2f(0.0f, 0.0f);
44 glVertex2f(0.0f, y + 0.2f);
49 glDisable(GL_TEXTURE_2D);
50 glColor3f(0.0f, 0.0f, 0.0f);
53 glVertex2f((0.1f + rad * cos(theta) * 0.1f) * 9.0f / 16.0f, y + 0.1f - rad * sin(theta) * 0.1f);
57 glDisable(GL_TEXTURE_2D);
60 glColor3f(0.0f, 0.0f, 0.0f);
61 glVertex2f(0.22f * 9.0f / 16.0f, y);
62 glVertex2f(0.24f * 9.0f / 16.0f, y);
64 glColor3f(1.0f, 1.0f, 1.0f);
65 glVertex2f(0.24f * 9.0f / 16.0f, y + 0.2f);
66 glVertex2f(0.22f * 9.0f / 16.0f, y + 0.2f);
71 glColor3f(0.0f, 0.0f, 0.0f);
74 glVertex2f(0.23f * 9.0f / 16.0f, y + value * 0.2f);
77 glColor3f(1.0f, 1.0f, 1.0f);
80 void draw_saturation_bar(float y, float saturation)
86 glDisable(GL_TEXTURE_2D);
89 glColor3f(0.0f, 0.0f, 0.0f);
90 glVertex2f(0.0f * 9.0f / 16.0f, y + 0.02f);
91 glVertex2f(0.0f * 9.0f / 16.0f, y);
93 glColor3f(1.0f, 1.0f, 1.0f);
94 glVertex2f(0.2f * 9.0f / 16.0f, y);
95 glVertex2f(0.2f * 9.0f / 16.0f, y + 0.02f);
100 glColor3f(0.0f, 0.0f, 0.0f);
103 glVertex2f(0.2f * saturation * 9.0f / 16.0f, y + 0.01f);
106 glColor3f(1.0f, 1.0f, 1.0f);
109 void make_hsv_wheel_texture()
111 glGenTextures(1, &hsv_wheel_num);
113 static unsigned char hsv_pix[HSV_WHEEL_SIZE * HSV_WHEEL_SIZE * 4];
114 for (int y = 0; y < HSV_WHEEL_SIZE; ++y) {
115 for (int x = 0; x < HSV_WHEEL_SIZE; ++x) {
116 float yf = 2.0f * y / (float)(HSV_WHEEL_SIZE) - 1.0f;
117 float xf = 2.0f * x / (float)(HSV_WHEEL_SIZE) - 1.0f;
118 float rad = hypot(xf, yf);
119 float theta = atan2(yf, xf);
122 hsv2rgb(theta, rad, 1.0f, &r, &g, &b);
123 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 0] = lrintf(r * 255.0f);
124 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 1] = lrintf(g * 255.0f);
125 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 2] = lrintf(b * 255.0f);
128 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 3] = 0;
130 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 3] = 255;
135 glBindTexture(GL_TEXTURE_2D, hsv_wheel_num);
137 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
139 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, HSV_WHEEL_SIZE, HSV_WHEEL_SIZE, 0, GL_RGBA, GL_UNSIGNED_BYTE, hsv_pix);
143 void read_colorwheel(float xf, float yf, float *rad, float *theta, float *value)
145 if (xf < 0.2f && yf < 0.2f) {
146 float xp = 2.0f * xf / 0.2f - 1.0f;
147 float yp = -(2.0f * yf / 0.2f - 1.0f);
148 *rad = hypot(xp, yp);
149 *theta = atan2(yp, xp);
153 } else if (xf >= 0.22f && xf <= 0.24f) {