Zack Buhman
9610c428bd
This draws a nice macaw texture in a square-shaped triangle strip. The square is then rotated around the y-axis. I dealt with myriad bugs while experimenting with this, all of them entirely my fault: - macaw texture colors were incorrect because GIMP was exporting raw RGB data in gamma-corrected sRGB space, whereas the Dreamcast is in linear color space. - macaw texture colors were incorrect because I truncated color values to the least significant rather than most significant bits. - macaw rotation around the Y axis caused the macaw texture to distort, stretch and recurse in interesting and unexpected ways. This was caused by sending Z values in the wrong coordinate space (Z) contrast to what is expected by the Dreamcast (1/z). Reordering z-coordinate operations so that the reciprocal is computed last resolved this. - macaw rotation around the Y axis caused the macaw texture to warp unexpectedly, but only on real hardware. This was caused by unnecessarily negating Z coordinate values. Behavior for each of the Z-coordinate issues differed between Flycast and real Dreamcast hardware. I also did several tests related to SH4 cache behavior, particularly related to the "copy-back" mode. I verified copy-back behavior on a real dreamcast, and experimented with the operand cache write-back instruction, "ocbwb". In particular, when the `scene` buffer is access from cacheable memory, e.g: the P1 area, and CCR__CB is enabled, DMA from physical memory to the TA FIFO polygon converter will fail because the scene data has not yet been written to physical memory yet. `ocbwb` can be used to "write back" scene from the SH4 operand cache to physical memory--only the latter is visible from the CH2-DMA perspective.
84 lines
3.0 KiB
C++
84 lines
3.0 KiB
C++
#include "float_uint32.h"
|
|
#include "core_bits.h"
|
|
#include "../holly.h"
|
|
#include "../memorymap.h"
|
|
|
|
#include "texture_memory_alloc.h"
|
|
|
|
#include "core.h"
|
|
#include "background.h"
|
|
#include "region_array.h"
|
|
|
|
void core_init()
|
|
{
|
|
holly.ISP_FEED_CFG = isp_feed_cfg::cache_size_for_translucency(0x200);
|
|
|
|
holly.FPU_SHAD_SCALE = fpu_shad_scale::scale_factor_for_shadows(1);
|
|
holly.FPU_CULL_VAL = _i(1.f);
|
|
holly.FPU_PERP_VAL = _i(0.f);
|
|
holly.SPAN_SORT_CFG = span_sort_cfg::span_sort_enable
|
|
| span_sort_cfg::offset_sort_enable;
|
|
|
|
holly.FOG_COL_RAM = fog_col_ram::red(127)
|
|
| fog_col_ram::green(127)
|
|
| fog_col_ram::blue(127);
|
|
|
|
holly.FOG_COL_VERT = fog_col_vert::red(127)
|
|
| fog_col_vert::green(127)
|
|
| fog_col_vert::blue(127);
|
|
|
|
holly.FOG_CLAMP_MIN = fog_clamp_min::alpha(0)
|
|
| fog_clamp_min::red(0)
|
|
| fog_clamp_min::green(0)
|
|
| fog_clamp_min::blue(0);
|
|
|
|
holly.FOG_CLAMP_MAX = fog_clamp_max::alpha(255)
|
|
| fog_clamp_max::red(255)
|
|
| fog_clamp_max::green(255)
|
|
| fog_clamp_max::blue(255);
|
|
|
|
holly.HALF_OFFSET = half_offset::tsp_texel_sampling_position::center
|
|
| half_offset::tsp_pixel_sampling_position::center
|
|
| half_offset::fpu_pixel_sampling_position::center;
|
|
|
|
holly.FPU_PARAM_CFG = fpu_param_cfg::region_header_type::type_2
|
|
| fpu_param_cfg::tsp_parameter_burst_threshold(31)
|
|
| fpu_param_cfg::isp_parameter_burst_threshold(31)
|
|
| fpu_param_cfg::pointer_burst_size(7) // must be less than opb size
|
|
| fpu_param_cfg::pointer_first_burst_size(7); // half of pointer burst size(?)
|
|
}
|
|
|
|
void core_init_texture_memory()
|
|
{
|
|
volatile texture_memory_alloc * mem = reinterpret_cast<volatile texture_memory_alloc *>(texture_memory);
|
|
|
|
background_parameter(mem->background);
|
|
region_array(mem->region_array,
|
|
(offsetof (struct texture_memory_alloc, object_list)),
|
|
640 / 32, // width
|
|
480 / 32 // height
|
|
);
|
|
}
|
|
|
|
void core_start_render(int fb)
|
|
{
|
|
holly.REGION_BASE = (offsetof (struct texture_memory_alloc, region_array));
|
|
holly.PARAM_BASE = (offsetof (struct texture_memory_alloc, isp_tsp_parameters));
|
|
|
|
holly.ISP_BACKGND_T = isp_backgnd_t::tag_address((offsetof (struct texture_memory_alloc, background)) / 4)
|
|
| isp_backgnd_t::tag_offset(0)
|
|
| isp_backgnd_t::skip(1);
|
|
holly.ISP_BACKGND_D = _i(1.f/100000);
|
|
|
|
holly.FB_W_CTRL = 1 << 3 | fb_w_ctrl::fb_packmode::_565_rgb_16bit;
|
|
holly.FB_W_LINESTRIDE = (640 * 2) / 8;
|
|
|
|
int w_fb = (!(!fb)) * 0x00096000;
|
|
int r_fb = (!fb) * 0x00096000;
|
|
holly.FB_W_SOF1 = (offsetof (struct texture_memory_alloc, framebuffer)) + w_fb;
|
|
//holly.FB_R_SOF1 = (offsetof (struct texture_memory_alloc, framebuffer)) + r_fb;
|
|
holly.FB_R_SOF1 = (offsetof (struct texture_memory_alloc, framebuffer)) + w_fb;
|
|
|
|
holly.STARTRENDER = 1;
|
|
}
|