Changeset 1067Tweet

Timestamp:

Nov 14, 2011, 11:37:39 PM (11 years ago)

Author:

sam

Message:

tutorial: use a palette for the rendering; it gives us free dithering and
gains 10 milliseconds in the game tick.

File:

• trunk/test/tutorial/tut03.cpp (modified) (6 diffs)

trunk/test/tutorial/tut03.cpp

@@ -51 +51 @@
         m_ready = false;
 
+        m_palette = new u8vec4[MAX_ITERATIONS * PALETTE_STEP];
+        for (int i = 0; i < MAX_ITERATIONS * PALETTE_STEP; i++)
+        {
+            float f = i / (double)PALETTE_STEP;
+
+            double r = 0.5 * sin(f * 0.27 - 1.5) + 0.5;
+            double g = 0.5 * sin(f * 0.13 + 1.3) + 0.5;
+            double b = 0.5 * sin(f * 0.21 + 0.4) + 0.5;
+
+            uint8_t red = r * 255.0f;
+            uint8_t green = g * 255.0f;
+            uint8_t blue = b * 255.0f;
+            m_palette[i] = u8vec4(red, green, blue, 0);
+        }
+
         m_centertext = new Text(NULL, "gfx/font/ascii.png");
         m_centertext->SetPos(ivec3(5, m_size.y - 15, 1));
@@ -77 +92 @@
         delete m_pixels;
         delete m_tmppixels;
+        delete m_palette;
     }
 
@@ -143 +159 @@
             {
                 double const maxlen = 32;
-                int const maxiter = 170;
 
                 f64cmplx z0 = m_center + ScreenToWorldOffset(ivec2(i, j));
@@ -153 +168 @@
                 //f64cmplx r0(0.3245046418497685, 0.04855101129280834);
                 f64cmplx z;
-                int iter = maxiter;
+                int iter = MAX_ITERATIONS;
                 for (z = z0; iter && z.sqlen() < maxlen * maxlen; z = z * z + r0)
                     --iter;
 
-                double f = iter;
-                double n = z.sqlen();
-
-                double k = log(n) * 0.5f / log(maxlen);
-                /* Approximate log2(k) in [1,2]. */
-                f += (- 0.344847817623168308695977510213252644185 * k
-                      + 2.024664188044341212602376988171727038739) * k
-                      - 1.674876738008591047163498125918330313237;
-
                 if (iter)
                 {
-                    double r = 0.5 * sin(f * 0.27 - 1.5) + 0.5;
-                    double g = 0.5 * sin(f * 0.13 + 1.3) + 0.5;
-                    double b = 0.5 * sin(f * 0.21 + 0.4) + 0.5;
-
-                    uint8_t red = r * 255.0f;
-                    uint8_t green = g * 255.0f;
-                    uint8_t blue = b * 255.0f;
-                    *m_pixelstart++ = u8vec4(red, green, blue, 0);
+                    double f = iter;
+                    double n = z.sqlen();
+
+                    double k = log(n) * 0.5f / log(maxlen);
+                    /* Approximate log2(k) in [1,2]. */
+                    f += (- 0.344847817623168308695977510213252644185 * k
+                          + 2.024664188044341212602376988171727038739) * k
+                          - 1.674876738008591047163498125918330313237;
+
+                    *m_pixelstart++ = m_palette[(int)(f * PALETTE_STEP + 0.25 * m_frame)];
                 }
                 else
@@ -306 +314 @@
 
 /* If other frames are dirty, upload fake data for now */
-for (int i = 0; i < 4; i++)
+if (0) for (int i = 0; i < 4; i++)
 {
     if (m_dirty[i])
@@ -359 +367 @@
 
 private:
+    static int const MAX_ITERATIONS = 170;
+    static int const PALETTE_STEP = 32;
+
     ivec2 m_size;
-    u8vec4 *m_pixels, *m_tmppixels;
+    u8vec4 *m_pixels, *m_tmppixels, *m_palette;
     Shader *m_shader;
     GLuint m_texid;