7 #define HSV_WHEEL_SIZE 128
13 void draw_hsv_wheel(float y, float rad, float theta, float value)
17 glActiveTexture(GL_TEXTURE0);
19 glEnable(GL_TEXTURE_2D);
21 glBindTexture(GL_TEXTURE_2D, hsv_wheel_num);
23 glActiveTexture(GL_TEXTURE1);
25 glBindTexture(GL_TEXTURE_2D, 0);
27 glActiveTexture(GL_TEXTURE0);
30 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
36 glTexCoord2f(0.0f, 1.0f);
39 glTexCoord2f(1.0f, 1.0f);
40 glVertex2f(0.2f * 9.0f / 16.0f, y);
42 glTexCoord2f(1.0f, 0.0f);
43 glVertex2f(0.2f * 9.0f / 16.0f, y + 0.2f);
45 glTexCoord2f(0.0f, 0.0f);
46 glVertex2f(0.0f, y + 0.2f);
51 glDisable(GL_TEXTURE_2D);
52 glColor3f(0.0f, 0.0f, 0.0f);
55 glVertex2f((0.1f + rad * cos(theta) * 0.1f) * 9.0f / 16.0f, y + 0.1f - rad * sin(theta) * 0.1f);
59 glDisable(GL_TEXTURE_2D);
62 glColor3f(0.0f, 0.0f, 0.0f);
63 glVertex2f(0.22f * 9.0f / 16.0f, y);
64 glVertex2f(0.24f * 9.0f / 16.0f, y);
66 glColor3f(1.0f, 1.0f, 1.0f);
67 glVertex2f(0.24f * 9.0f / 16.0f, y + 0.2f);
68 glVertex2f(0.22f * 9.0f / 16.0f, y + 0.2f);
73 glColor3f(0.0f, 0.0f, 0.0f);
76 glVertex2f(0.23f * 9.0f / 16.0f, y + value * 0.2f);
79 glColor3f(1.0f, 1.0f, 1.0f);
82 void draw_saturation_bar(float y, float saturation)
88 glDisable(GL_TEXTURE_2D);
91 glColor3f(0.0f, 0.0f, 0.0f);
92 glVertex2f(0.0f * 9.0f / 16.0f, y + 0.02f);
93 glVertex2f(0.0f * 9.0f / 16.0f, y);
95 glColor3f(1.0f, 1.0f, 1.0f);
96 glVertex2f(0.2f * 9.0f / 16.0f, y);
97 glVertex2f(0.2f * 9.0f / 16.0f, y + 0.02f);
102 glColor3f(0.0f, 0.0f, 0.0f);
105 glVertex2f(0.2f * saturation * 9.0f / 16.0f, y + 0.01f);
108 glColor3f(1.0f, 1.0f, 1.0f);
111 void make_hsv_wheel_texture()
113 glGenTextures(1, &hsv_wheel_num);
115 static unsigned char hsv_pix[HSV_WHEEL_SIZE * HSV_WHEEL_SIZE * 4];
116 for (int y = 0; y < HSV_WHEEL_SIZE; ++y) {
117 for (int x = 0; x < HSV_WHEEL_SIZE; ++x) {
118 float yf = 2.0f * y / (float)(HSV_WHEEL_SIZE) - 1.0f;
119 float xf = 2.0f * x / (float)(HSV_WHEEL_SIZE) - 1.0f;
120 float rad = hypot(xf, yf);
121 float theta = atan2(yf, xf);
124 hsv2rgb(theta, rad, 1.0f, &r, &g, &b);
125 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 0] = lrintf(r * 255.0f);
126 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 1] = lrintf(g * 255.0f);
127 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 2] = lrintf(b * 255.0f);
130 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 3] = 0;
132 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 3] = 255;
137 glBindTexture(GL_TEXTURE_2D, hsv_wheel_num);
139 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
141 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, HSV_WHEEL_SIZE, HSV_WHEEL_SIZE, 0, GL_RGBA, GL_UNSIGNED_BYTE, hsv_pix);
145 void read_colorwheel(float xf, float yf, float *rad, float *theta, float *value)
147 if (xf < 0.2f && yf < 0.2f) {
148 float xp = 2.0f * xf / 0.2f - 1.0f;
149 float yp = -(2.0f * yf / 0.2f - 1.0f);
150 *rad = hypot(xp, yp);
151 *theta = atan2(yp, xp);
155 } else if (xf >= 0.22f && xf <= 0.24f) {