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-rw-r--r--color.c138
-rw-r--r--graphics.h4
-rw-r--r--mkfile1
-rw-r--r--render.c4
-rw-r--r--texture.c18
5 files changed, 150 insertions, 15 deletions
diff --git a/color.c b/color.c
new file mode 100644
index 0000000..cdd089f
--- /dev/null
+++ b/color.c
@@ -0,0 +1,138 @@
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include <draw.h>
+#include <memdraw.h>
+#include <geometry.h>
+#include "libobj/obj.h"
+#include "graphics.h"
+#include "internal.h"
+
+/*
+ * generated with:
+ * % seq 0 255 | awk '{$0 = $0/255; if($0 > 0.04045) $0 = (($0+0.055)/1.055)^2.4; else $0 = $0/12.92; printf("\t0x%02X,%s", int($0*255+0.5), NR%8 == 0? "\n": "")}'
+ */
+static uchar srgb2lineartab[] = {
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+ 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+ 0x01, 0x01, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
+ 0x02, 0x02, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
+ 0x04, 0x04, 0x04, 0x04, 0x04, 0x05, 0x05, 0x05,
+ 0x05, 0x06, 0x06, 0x06, 0x06, 0x07, 0x07, 0x07,
+ 0x08, 0x08, 0x08, 0x08, 0x09, 0x09, 0x09, 0x0A,
+ 0x0A, 0x0A, 0x0B, 0x0B, 0x0C, 0x0C, 0x0C, 0x0D,
+ 0x0D, 0x0D, 0x0E, 0x0E, 0x0F, 0x0F, 0x10, 0x10,
+ 0x11, 0x11, 0x11, 0x12, 0x12, 0x13, 0x13, 0x14,
+ 0x14, 0x15, 0x16, 0x16, 0x17, 0x17, 0x18, 0x18,
+ 0x19, 0x19, 0x1A, 0x1B, 0x1B, 0x1C, 0x1D, 0x1D,
+ 0x1E, 0x1E, 0x1F, 0x20, 0x20, 0x21, 0x22, 0x23,
+ 0x23, 0x24, 0x25, 0x25, 0x26, 0x27, 0x28, 0x29,
+ 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2D, 0x2E, 0x2F,
+ 0x30, 0x31, 0x32, 0x33, 0x33, 0x34, 0x35, 0x36,
+ 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E,
+ 0x3F, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46,
+ 0x47, 0x48, 0x49, 0x4A, 0x4C, 0x4D, 0x4E, 0x4F,
+ 0x50, 0x51, 0x52, 0x54, 0x55, 0x56, 0x57, 0x58,
+ 0x5A, 0x5B, 0x5C, 0x5D, 0x5F, 0x60, 0x61, 0x63,
+ 0x64, 0x65, 0x67, 0x68, 0x69, 0x6B, 0x6C, 0x6D,
+ 0x6F, 0x70, 0x72, 0x73, 0x74, 0x76, 0x77, 0x79,
+ 0x7A, 0x7C, 0x7D, 0x7F, 0x80, 0x82, 0x83, 0x85,
+ 0x86, 0x88, 0x8A, 0x8B, 0x8D, 0x8E, 0x90, 0x92,
+ 0x93, 0x95, 0x97, 0x98, 0x9A, 0x9C, 0x9D, 0x9F,
+ 0xA1, 0xA3, 0xA4, 0xA6, 0xA8, 0xAA, 0xAB, 0xAD,
+ 0xAF, 0xB1, 0xB3, 0xB5, 0xB7, 0xB8, 0xBA, 0xBC,
+ 0xBE, 0xC0, 0xC2, 0xC4, 0xC6, 0xC8, 0xCA, 0xCC,
+ 0xCE, 0xD0, 0xD2, 0xD4, 0xD6, 0xD8, 0xDA, 0xDC,
+ 0xDE, 0xE0, 0xE2, 0xE5, 0xE7, 0xE9, 0xEB, 0xED,
+ 0xEF, 0xF2, 0xF4, 0xF6, 0xF8, 0xFA, 0xFD, 0xFF,
+};
+
+/*
+ * generated with:
+ * % seq 0 255 | awk '{$0 = $0/255.0; if($0 > 0.0031308) $0 = 1.055*$0^(1.0/2.4)-0.055; else $0 = $0*12.92; printf("\t0x%02X,%s", int($0*255+0.5), NR%8 == 0? "\n": "")}'
+ */
+static uchar linear2srgbtab[] = {
+ 0x00, 0x0D, 0x16, 0x1C, 0x22, 0x26, 0x2A, 0x2E,
+ 0x32, 0x35, 0x38, 0x3B, 0x3D, 0x40, 0x42, 0x45,
+ 0x47, 0x49, 0x4B, 0x4D, 0x4F, 0x51, 0x53, 0x55,
+ 0x56, 0x58, 0x5A, 0x5C, 0x5D, 0x5F, 0x60, 0x62,
+ 0x63, 0x65, 0x66, 0x68, 0x69, 0x6A, 0x6C, 0x6D,
+ 0x6E, 0x70, 0x71, 0x72, 0x73, 0x75, 0x76, 0x77,
+ 0x78, 0x79, 0x7A, 0x7C, 0x7D, 0x7E, 0x7F, 0x80,
+ 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88,
+ 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90,
+ 0x91, 0x92, 0x93, 0x94, 0x94, 0x95, 0x96, 0x97,
+ 0x98, 0x99, 0x9A, 0x9B, 0x9B, 0x9C, 0x9D, 0x9E,
+ 0x9F, 0x9F, 0xA0, 0xA1, 0xA2, 0xA3, 0xA3, 0xA4,
+ 0xA5, 0xA6, 0xA7, 0xA7, 0xA8, 0xA9, 0xAA, 0xAA,
+ 0xAB, 0xAC, 0xAD, 0xAD, 0xAE, 0xAF, 0xAF, 0xB0,
+ 0xB1, 0xB2, 0xB2, 0xB3, 0xB4, 0xB4, 0xB5, 0xB6,
+ 0xB6, 0xB7, 0xB8, 0xB9, 0xB9, 0xBA, 0xBB, 0xBB,
+ 0xBC, 0xBD, 0xBD, 0xBE, 0xBE, 0xBF, 0xC0, 0xC0,
+ 0xC1, 0xC2, 0xC2, 0xC3, 0xC4, 0xC4, 0xC5, 0xC5,
+ 0xC6, 0xC7, 0xC7, 0xC8, 0xC8, 0xC9, 0xCA, 0xCA,
+ 0xCB, 0xCB, 0xCC, 0xCD, 0xCD, 0xCE, 0xCE, 0xCF,
+ 0xD0, 0xD0, 0xD1, 0xD1, 0xD2, 0xD2, 0xD3, 0xD4,
+ 0xD4, 0xD5, 0xD5, 0xD6, 0xD6, 0xD7, 0xD7, 0xD8,
+ 0xD8, 0xD9, 0xDA, 0xDA, 0xDB, 0xDB, 0xDC, 0xDC,
+ 0xDD, 0xDD, 0xDE, 0xDE, 0xDF, 0xDF, 0xE0, 0xE0,
+ 0xE1, 0xE2, 0xE2, 0xE3, 0xE3, 0xE4, 0xE4, 0xE5,
+ 0xE5, 0xE6, 0xE6, 0xE7, 0xE7, 0xE8, 0xE8, 0xE9,
+ 0xE9, 0xEA, 0xEA, 0xEB, 0xEB, 0xEC, 0xEC, 0xED,
+ 0xED, 0xEE, 0xEE, 0xEE, 0xEF, 0xEF, 0xF0, 0xF0,
+ 0xF1, 0xF1, 0xF2, 0xF2, 0xF3, 0xF3, 0xF4, 0xF4,
+ 0xF5, 0xF5, 0xF6, 0xF6, 0xF6, 0xF7, 0xF7, 0xF8,
+ 0xF8, 0xF9, 0xF9, 0xFA, 0xFA, 0xFB, 0xFB, 0xFB,
+ 0xFC, 0xFC, 0xFD, 0xFD, 0xFE, 0xFE, 0xFF, 0xFF,
+};
+
+/*
+ * Equations 5.32 and 5.30 from “Display Encoding”, Real-Time Rendering 4th ed. § 5.6
+ */
+//static double
+//_srgb2linear(double c)
+//{
+// if(c > 0.04045)
+// return pow((c + 0.055)/1.055, 2.4);
+// return c/12.92;
+//}
+//
+//static double
+//_linear2srgb(double c)
+//{
+// if(c > 0.0031308)
+// return 1.055*pow(c, 1.0/2.4) - 0.055;
+// return 12.92*c;
+//}
+
+static double
+_srgb2linear(double c)
+{
+ c = fclamp(c, 0, 1);
+ return srgb2lineartab[(int)(c*255)]/255.0;
+}
+
+static double
+_linear2srgb(double c)
+{
+ c = fclamp(c, 0, 1);
+ return linear2srgbtab[(int)(c*255)]/255.0;
+}
+
+Color
+srgb2linear(Color c)
+{
+ c.r = _srgb2linear(c.r);
+ c.g = _srgb2linear(c.g);
+ c.b = _srgb2linear(c.b);
+ return c;
+}
+
+Color
+linear2srgb(Color c)
+{
+ c.r = _linear2srgb(c.r);
+ c.g = _linear2srgb(c.g);
+ c.b = _linear2srgb(c.b);
+ return c;
+}
diff --git a/graphics.h b/graphics.h
index 7b46ed7..335b4b0 100644
--- a/graphics.h
+++ b/graphics.h
@@ -339,6 +339,10 @@ Point2 modulapt2(Point2, Point2);
Point3 modulapt3(Point3, Point3);
Memimage *rgb(ulong);
+/* color */
+Color srgb2linear(Color);
+Color linear2srgb(Color);
+
/* shadeop */
double sign(double);
double step(double, double);
diff --git a/mkfile b/mkfile
index 16559b9..ffdd953 100644
--- a/mkfile
+++ b/mkfile
@@ -13,6 +13,7 @@ OFILES=\
alloc.$O\
fb.$O\
shadeop.$O\
+ color.$O\
util.$O\
nanosec.$O\
diff --git a/render.c b/render.c
index 7fb3ae5..563df69 100644
--- a/render.c
+++ b/render.c
@@ -41,9 +41,9 @@ pixel(Framebuf *fb, Point p, Color c)
ulong *dst;
dst = fb->cb;
- dc = ul2col(dst[Dx(fb->r)*p.y + p.x]);
+ dc = srgb2linear(ul2col(dst[Dx(fb->r)*p.y + p.x]));
c = lerp3(dc, c, c.a); /* SoverD */
- dst[Dx(fb->r)*p.y + p.x] = col2ul(c);
+ dst[Dx(fb->r)*p.y + p.x] = col2ul(linear2srgb(c));
}
static void
diff --git a/texture.c b/texture.c
index 158bcb6..d51076e 100644
--- a/texture.c
+++ b/texture.c
@@ -29,18 +29,6 @@ uv2tp(Point2 uv, Memimage *i)
}
static Color
-ul2col(ulong l)
-{
- Color c;
-
- c.a = (l & 0xff)/255.0;
- c.b = (l>>8 & 0xff)/255.0;
- c.g = (l>>16 & 0xff)/255.0;
- c.r = (l>>24 & 0xff)/255.0;
- return c;
-}
-
-static Color
cbuf2col(uchar b[4])
{
Color c;
@@ -72,7 +60,11 @@ _memreadcolor(Memimage *i, Point sp)
break;
}
- return cbuf2col(cbuf);
+ /* TODO
+ * not all textures require color space conversion. implement a better
+ * interface to let the user decide.
+ */
+ return srgb2linear(cbuf2col(cbuf));
}
/*