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Fixed line drawing example.

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This commit is contained in:
jespergravgaard 2021-04-03 21:35:20 +02:00
parent 65eb2edc12
commit ad92cea393
1 changed files with 16 additions and 19 deletions
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27
src/test/kc/examples/mega65/linedrawing.c
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@ -1,7 +1,7 @@
// Test hardware line drawing
// Based on https://github.com/MEGA65/mega65-tools/blob/master/src/tests/test_290.c
#pragma target(mega65)
#pragma target(mega65_remote)
#include <mega65.h>
#include <mega65-dma.h>
#include <6502.h>
@ -40,8 +40,8 @@ void lpoke(__zp unsigned long addr, char val) {
// Graphics mode is 1 byte per pixel. Addressing is based on columns of 8px * 200px arranged to have linear addressing.
// addr = (x/8) * 64 * 25 + (y*8) + (x&7)
char line_dma_command[] = {
DMA_OPTION_LINE_XSTEP_LO, LOBYTE(25*64 - 8), // Line X step bytes 64x25
DMA_OPTION_LINE_XSTEP_HI, HIBYTE(25*64 - 8), // Line X step bytes 64x25
DMA_OPTION_LINE_XSTEP_LO, (25*64 - 8) & 0xff, // Line X step bytes 64x25
DMA_OPTION_LINE_XSTEP_HI, (25*64 - 8) >> 8, // Line X step bytes 64x25
DMA_OPTION_LINE_SLOPE_LO, 0, // Line Slope
DMA_OPTION_LINE_SLOPE_HI, 0, // Line Slope
DMA_OPTION_LINE_SLOPE_INIT_LO, LOBYTE(32768), // Line slope init
@ -69,7 +69,7 @@ const char LINE_DMA_COMMAND_SRC_OFFSET = 19;
// Offset of the DMA destination
const char LINE_DMA_COMMAND_DEST_OFFSET = 22;
void line_dma_execute(unsigned long addr, unsigned int slope, unsigned int count, char colour, char is_direction_y, char is_slope_negative) {
void line_dma_execute( unsigned long addr, unsigned int slope, unsigned int count, char colour, char is_slope_negative, char is_direction_y) {
// Put slope into DMA options
line_dma_command[LINE_DMA_COMMAND_SLOPE_OFFSET] = LOBYTE(slope);
@ -87,8 +87,8 @@ void line_dma_execute(unsigned long addr, unsigned int slope, unsigned int count
line_dma_command[LINE_DMA_COMMAND_COUNT_OFFSET] = LOBYTE(count);
line_dma_command[LINE_DMA_COMMAND_COUNT_OFFSET + 1] = HIBYTE(count);
// Line mode active, major axis is Y
line_dma_command[LINE_DMA_COMMAND_MODE_OFFSET] = DMA_OPTION_LINE_MODE_ENABLE + (is_direction_y ? DMA_OPTION_LINE_MODE_DIRECTION_Y : 0x00) + (is_slope_negative ? DMA_OPTION_LINE_MODE_SLOPE_NEGATIVE : 0x00);
// Line mode active, major axis is X
line_dma_command[LINE_DMA_COMMAND_MODE_OFFSET] = DMA_OPTION_LINE_MODE_ENABLE + (is_direction_y?DMA_OPTION_LINE_MODE_DIRECTION_Y:0) + (is_slope_negative?DMA_OPTION_LINE_MODE_SLOPE_NEGATIVE:0);
// Set address of DMA list
DMA->ADDRMB = 0;
@ -230,13 +230,12 @@ void draw_line(int x1, int y1, int x2, int y2, unsigned char colour) {
lda MATH_DIVOUT_FRAC_INT1 @nooptimize
}
// Slope is the most significant bytes of the fractional part of the division result
// Perform rounding by examining the next bit also
unsigned int slope = (unsigned int)*MATH_DIVOUT_FRAC_INT1 + (((char)*MATH_DIVOUT_FRAC_CHAR1&0x80)?1:0);
unsigned int slope_init = 32768;
unsigned int slope = (unsigned int)*MATH_DIVOUT_FRAC_INT1;
unsigned long addr = GRAPHICS + (unsigned int)(x1/8) * 64 * 25 + (unsigned int)(y1*8) + (unsigned char)(x1&7);
unsigned int count = (unsigned int)dy;
char is_slope_negative = ((x2 - x1) < 0) ? 1 : 0;
line_dma_execute(addr, slope, count, colour, 1, is_slope_negative);
char is_direction_y = 1;
line_dma_execute(addr, slope, count, colour, is_slope_negative, is_direction_y);
} else {
// X is major axis
@ -262,14 +261,12 @@ void draw_line(int x1, int y1, int x2, int y2, unsigned char colour) {
lda MATH_DIVOUT_FRAC_INT1 @nooptimize
lda MATH_DIVOUT_FRAC_INT1 @nooptimize
}
// Slope is the most significant bytes of the fractional part of the division result
// Perform rounding by examining the next bit also
unsigned int slope = (unsigned int)*MATH_DIVOUT_FRAC_INT1 + (((char)*MATH_DIVOUT_FRAC_CHAR1&0x80)?1:0);
unsigned int slope = (unsigned int)*MATH_DIVOUT_FRAC_INT1;
unsigned long addr = GRAPHICS + (unsigned int)(x1/8) * 64 * 25 + (unsigned int)(y1*8) + (unsigned char)(x1&7);
unsigned int count = (unsigned int)dx;
char is_slope_negative = ((y2 - y1) < 0) ? 1 : 0;
line_dma_execute(addr, slope, count, colour, 0, is_slope_negative);
char is_direction_y = 0;
line_dma_execute(addr, slope, count, colour, is_slope_negative, is_direction_y);
}
}