mirror of https://github.com/inolen/redream.git
simplify excessive calculations on the z components coming from the TA which were causing depth buffer precision issues in many games
This commit is contained in:
Anthony Pesch
parent
c6b6bcfc76
commit
e39c1ffae6
117
src/hw/pvr/tr.c
117
src/hw/pvr/tr.c
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@ -119,12 +119,9 @@ static inline uint32_t float_to_rgba(float r, float g, float b, float a) {
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static texture_handle_t tr_demand_texture(struct tr *tr,
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const struct tile_ctx *ctx, int frame,
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union tsp tsp, union tcw tcw) {
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/*
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* TODO
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* it's bad that textures are only cached based off tsp / tcw yet the
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* TEXT_CONTROL registers and PAL_RAM_CTRL registers are used here to
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* control texture generation
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*/
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/* TODO it's bad that textures are only cached based off tsp / tcw yet the
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TEXT_CONTROL registers and PAL_RAM_CTRL registers are used here to control
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texture generation */
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struct texture_entry *entry =
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tr->provider->find_texture(tr->provider->data, tsp, tcw);
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@ -141,11 +138,9 @@ static texture_handle_t tr_demand_texture(struct tr *tr,
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entry->handle = 0;
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}
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/*
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* sanity check that the texture source is valid for the current frame. video
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* ram will be modified between frames, if these values don't match something
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* is broken in the ta's thread synchronization
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*/
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/* sanity check that the texture source is valid for the current frame. video
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ram will be modified between frames, if these values don't match something
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is broken in the ta's thread synchronization */
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CHECK_EQ(frame, entry->frame);
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static uint8_t converted[1024 * 1024 * 4];
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@ -154,10 +149,8 @@ static texture_handle_t tr_demand_texture(struct tr *tr,
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const uint8_t *input = texture;
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const uint8_t *output = texture;
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/*
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* textures are either twiddled and vq compressed, twiddled and uncompressed
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* or planar
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*/
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/* textures are either twiddled and vq compressed, twiddled and uncompressed
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or planar */
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bool twiddled = !tcw.scan_order;
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bool compressed = tcw.vq_compressed;
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bool mip_mapped = !tcw.scan_order && tcw.mip_mapped;
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@ -170,16 +163,12 @@ static texture_handle_t tr_demand_texture(struct tr *tr,
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stride = ctx->stride;
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}
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/*
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* mipmap textures contain data for 1 x 1 up to width x height. skip to the
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* highest res texture and let the renderer backend generate its own mipmaps
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*/
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/* mipmap textures contain data for 1 x 1 up to width x height. skip to the
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highest res and let the renderer backend generate its own mipmaps */
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if (mip_mapped) {
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if (compressed) {
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/*
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* for vq compressed textures the offset is only for the index data, the
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* codebook is the same for all levels
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*/
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/* for vq compressed textures the offset is only for the index data, the
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codebook is the same for all levels */
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input += compressed_mipmap_offsets[tsp.texture_u_size];
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} else if (tcw.pixel_format == TA_PIXEL_4BPP) {
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input += paletted_4bpp_mipmap_offsets[tsp.texture_u_size];
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@ -369,11 +358,8 @@ static void tr_discard_incomplete_surf(struct tr *tr,
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}
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}
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/*
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* TODO
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* offload thiis to the GPU, generating shader for different combinations of
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* ISP/TSP parameters once the logic is ironed out
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*/
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/* FIXME offload this to the GPU, generating shader for different combinations
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of ISP/TSP parameters once the logic is ironed out */
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/* FIXME honor use alpha */
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/* FIXME honor ignore tex alpha */
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static void tr_parse_color(struct tr *tr, uint32_t base_color,
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@ -490,10 +476,8 @@ static void tr_parse_bg(struct tr *tr, const struct tile_ctx *ctx,
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offset = tr_parse_bg_vert(ctx, offset, v1);
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offset = tr_parse_bg_vert(ctx, offset, v2);
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/*
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* override the xyz values supplied by ISP_BACKGND_T. while the hardware docs
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* act like the should be correct, they're most definitely not in most cases
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*/
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/* override xyz values supplied by ISP_BACKGND_T. while the hardware docs act
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like they should be correct, they're most definitely not in most cases */
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v0->xyz[0] = 0.0f;
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v0->xyz[1] = (float)ctx->video_height;
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v0->xyz[2] = ctx->bg_depth;
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@ -514,10 +498,8 @@ static void tr_parse_bg(struct tr *tr, const struct tile_ctx *ctx,
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v3->uv[1] = v1->uv[1];
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}
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/*
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* this offset color implementation is not correct at all, see the
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* Texture/Shading Instruction in the union tsp instruction word
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*/
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/* this offset color implementation is not correct at all, see the
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Texture/Shading Instruction in the union tsp instruction word */
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static void tr_parse_poly_param(struct tr *tr, const struct tile_ctx *ctx,
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int frame, struct render_context *rctx,
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const uint8_t *data) {
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@ -653,11 +635,9 @@ static void tr_parse_vert_param(struct tr *tr, const struct tile_ctx *ctx,
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struct render_context *rctx,
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const uint8_t *data) {
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const union vert_param *param = (const union vert_param *)data;
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/*
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* if there is no need to change the Global Parameters, a Vertex Parameter
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* for the next polygon may be input immediately after inputting a Vertex
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* Parameter for which "End of Strip" was specified
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*/
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/* if there is no need to change the Global Parameters, a Vertex Parameter
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for the next polygon may be input immediately after inputting a Vertex
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Parameter for which "End of Strip" was specified */
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if (tr->last_vertex && tr->last_vertex->type0.pcw.end_of_strip) {
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tr_alloc_surf(tr, rctx, true);
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}
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@ -806,13 +786,11 @@ static void tr_parse_vert_param(struct tr *tr, const struct tile_ctx *ctx,
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break;
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}
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/*
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* in the case of the Polygon type, the last Vertex Parameter for an object
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* must have "End of Strip" specified. If Vertex Parameters with the "End of
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* Strip" specification were not input, but parameters other than the Vertex
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* Parameters were input, the polygon data in question is ignored and
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* an interrupt signal is output
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*/
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/* in the case of the Polygon type, the last Vertex Parameter for an object
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must have "End of Strip" specified. If Vertex Parameters with the "End of
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Strip" specification were not input, but parameters other than the Vertex
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Parameters were input, the polygon data in question is ignored and
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an interrupt signal is output */
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/* FIXME is this true for sprites which come through this path as well? */
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}
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@ -887,10 +865,8 @@ static void tr_parse_eol(struct tr *tr, const struct tile_ctx *ctx,
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struct render_context *rctx, const uint8_t *data) {
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tr_discard_incomplete_surf(tr, rctx);
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/*
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* sort transparent polys by their z value, from back to front. remember, in
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* dreamcast coordinates smaller z values are further away from the camera
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*/
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/* sort transparent polys by their z value, from back to front. remember, in
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dreamcast coordinates smaller z values are further away from the camera */
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if ((tr->list_type == TA_LIST_TRANSLUCENT ||
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tr->list_type == TA_LIST_TRANSLUCENT_MODVOL) &&
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ctx->autosort) {
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@ -902,20 +878,15 @@ static void tr_parse_eol(struct tr *tr, const struct tile_ctx *ctx,
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tr->last_sorted_surf = rctx->num_surfs;
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}
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/*
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* vertices coming into the TA are in window space, with the Z component being
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* 1/W. these coordinates need to be converted back to clip space in order to
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* be rendered with OpenGL, etc. while we want to perform an orthographic
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* projection on the vertices as they're already perspective correct, the
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* renderer backend will have to deal with setting the W component of each
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* in order to perspective correct the texture mapping
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*/
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static void tr_proj_mat(struct tr *tr, const struct tile_ctx *ctx,
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struct render_context *rctx) {
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/* this isn't a traditional projection matrix. xy components coming into the
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TA are in window space, while the z component is 1/w with +z headed into
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the screen. these coordinates need to be scaled back into ndc space, and
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z needs to be flipped so that -z is headed into the screen */
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float znear = FLT_MIN;
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float zfar = FLT_MAX;
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/* Z component is 1/W, so +Z is into the screen */
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for (int i = 0; i < rctx->num_verts; i++) {
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struct vertex *v = &rctx->verts[i];
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if (v->xyz[2] > znear) {
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@ -926,15 +897,9 @@ static void tr_proj_mat(struct tr *tr, const struct tile_ctx *ctx,
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}
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}
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/* fudge so Z isn't being mapped to exactly 0.0 and 1.0 */
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float zdepth = (znear - zfar) * 1.1f;
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/* fudge so z isn't mapped to exactly 0.0 and 1.0 */
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float zdepth = (znear - zfar) * 1.0001f;
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/* fix case where a single polygon being renderered */
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if (zdepth <= 0.0f) {
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zdepth = 1.0f;
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}
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/* convert from window space coordinates into clip space */
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rctx->projection[0] = 2.0f / (float)ctx->video_width;
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rctx->projection[4] = 0.0f;
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rctx->projection[8] = 0.0f;
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@ -947,8 +912,8 @@ static void tr_proj_mat(struct tr *tr, const struct tile_ctx *ctx,
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rctx->projection[2] = 0.0f;
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rctx->projection[6] = 0.0f;
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rctx->projection[10] = (-znear - zfar) / zdepth;
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rctx->projection[14] = (2.0f * zfar * znear) / zdepth;
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rctx->projection[10] = 2.0f / -zdepth;
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rctx->projection[14] = -2.0f * znear / -zdepth - 1.0f;
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rctx->projection[3] = 0.0f;
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rctx->projection[7] = 0.0f;
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@ -984,12 +949,10 @@ void tr_parse_context(struct tr *tr, const struct tile_ctx *ctx, int frame,
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while (data < end) {
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union pcw pcw = *(union pcw *)data;
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/*
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* FIXME
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* if Vertex Parameters with the "End of Strip" specification were not
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* input, but parameters other than the Vertex Parameters were input, the
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* polygon data in question is ignored and an interrupt signal is output
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*/
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/* FIXME if Vertex Parameters with the "End of Strip" specification were
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not input, but parameters other than the Vertex Parameters were input,
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the polygon data in question is ignored and an interrupt signal is
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output */
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switch (pcw.para_type) {
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/* control params */
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@ -331,10 +331,6 @@ static bool video_init_context(struct video_backend *video) {
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SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
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SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
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// request a 24-bit depth buffer. 16-bits isn't enough precision when
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// unprojecting dreamcast coordinates, see tr_proj_mat
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SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
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video->ctx = SDL_GL_CreateContext(video->window->handle);
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if (!video->ctx) {
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LOG_WARNING("OpenGL context creation failed: %s", SDL_GetError());
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@ -15,15 +15,11 @@ static const char *ta_vp =
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" var_offset_color = attr_offset_color;\n"
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" var_diffuse_texcoord = attr_texcoord;\n"
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" // convert from window space back into ndc space\n"
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" gl_Position = u_mvp * vec4(attr_xyz, 1.0);\n"
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" // z is in the range of -znear to +zfar, since the actual perspective divide\n"
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" // won't occur, do it manually\n"
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" gl_Position.z /= attr_xyz.z;\n"
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" // specify w so OpenGL applies perspective corrected texture mapping, but\n"
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" // cancel the perspective divide on the xyz, they're already perspective\n"
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" // correct\n"
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" // cancel the perspective divide on the xyz, they're already in ndc space\n"
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" float w = 1.0 / attr_xyz.z;\n"
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" gl_Position.xyz *= w;\n"
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" gl_Position.w = w;\n"
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