Created
August 2, 2021 05:03
-
-
Save yamamaya/a2bdfaae8cd35d1c0694b933d2bf61b7 to your computer and use it in GitHub Desktop.
Blend RGB555 colors together with "software packed" method
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| #include <stdint.h> | |
| uint16_t blendRGB555( uint16_t color1, uint16_t color2 ) { | |
| return( (color1 & color2) + (((color1 ^ color2) & 0x7bde) >> 1) ); | |
| } | |
| // testbench | |
| #include <stdio.h> | |
| #define R_bits 5 | |
| #define G_bits 5 | |
| #define B_bits 5 | |
| int main(void) { | |
| for ( uint16_t r1 = 0 ; r1 < ( 1 << R_bits ) ; r1 ++ ) { | |
| printf( "%d\n", r1 ); | |
| for ( uint16_t g1 = 0 ; g1 < ( 1 << G_bits ) ; g1 ++ ) { | |
| for ( uint16_t b1 = 0 ; b1 < ( 1 << B_bits ) ; b1 ++ ) { | |
| uint16_t color1 = ( r1 << ( G_bits + B_bits ) ) | ( g1 << B_bits ) | b1; | |
| for ( uint16_t r2 = 0 ; r2 < ( 1 << R_bits ) ; r2 ++ ) { | |
| for ( uint16_t g2 = 0 ; g2 < ( 1 << G_bits ) ; g2 ++ ) { | |
| for ( uint16_t b2 = 0 ; b2 < ( 1 << B_bits ) ; b2 ++ ) { | |
| uint16_t color2 = ( r2 << ( G_bits + B_bits ) ) | ( g2 << B_bits ) | b2; | |
| uint16_t r_expected = ( r1 + r2 ) / 2; | |
| uint16_t g_expected = ( g1 + g2 ) / 2; | |
| uint16_t b_expected = ( b1 + b2 ) / 2; | |
| uint16_t res = blendRGB555( color1, color2 ); | |
| uint16_t r_result = ( res >> ( G_bits + B_bits ) ) & ( ( 1 << R_bits ) - 1 ); | |
| uint16_t g_result = ( res >> B_bits ) & ( ( 1 << G_bits ) - 1 ); | |
| uint16_t b_result = res & ( ( 1 << B_bits ) - 1 ); | |
| if ( r_result != r_expected || g_result != g_expected || b_result != b_expected ) { | |
| printf( "\nWrong Answer: (%d,%d,%d) (%d,%d,%d) -> (%d,%d,%d) but expected (%d,%d,%d)\n", | |
| r1, g1, b1, | |
| r2, g2, b2, | |
| r_result, g_result, b_result, | |
| r_expected, g_expected, b_expected | |
| ); | |
| return 1; | |
| } | |
| } | |
| } | |
| } | |
| } | |
| } | |
| } | |
| printf( "Succeeded!\n" ); | |
| return 0; | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment