mirror of
https://github.com/mpv-player/mpv
synced 2024-11-14 22:48:35 +01:00
be230d16e5
This moves some of the bulky user-shader specific logic into the file dedicated to it. Rather than expose video.c state, variable lookup is now done via a simulated closure.
285 lines
8.7 KiB
C
285 lines
8.7 KiB
C
/*
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* This file is part of mpv.
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*
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* mpv is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* mpv is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with mpv. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <ctype.h>
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#include <assert.h>
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#include "user_shaders.h"
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static bool parse_rpn_szexpr(struct bstr line, struct szexp out[MAX_SZEXP_SIZE])
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{
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int pos = 0;
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while (line.len > 0) {
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struct bstr word = bstr_strip(bstr_splitchar(line, &line, ' '));
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if (word.len == 0)
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continue;
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if (pos >= MAX_SZEXP_SIZE)
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return false;
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struct szexp *exp = &out[pos++];
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if (bstr_eatend0(&word, ".w") || bstr_eatend0(&word, ".width")) {
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exp->tag = SZEXP_VAR_W;
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exp->val.varname = word;
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continue;
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}
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if (bstr_eatend0(&word, ".h") || bstr_eatend0(&word, ".height")) {
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exp->tag = SZEXP_VAR_H;
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exp->val.varname = word;
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continue;
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}
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switch (word.start[0]) {
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case '+': exp->tag = SZEXP_OP2; exp->val.op = SZEXP_OP_ADD; continue;
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case '-': exp->tag = SZEXP_OP2; exp->val.op = SZEXP_OP_SUB; continue;
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case '*': exp->tag = SZEXP_OP2; exp->val.op = SZEXP_OP_MUL; continue;
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case '/': exp->tag = SZEXP_OP2; exp->val.op = SZEXP_OP_DIV; continue;
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case '!': exp->tag = SZEXP_OP1; exp->val.op = SZEXP_OP_NOT; continue;
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case '>': exp->tag = SZEXP_OP2; exp->val.op = SZEXP_OP_GT; continue;
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case '<': exp->tag = SZEXP_OP2; exp->val.op = SZEXP_OP_LT; continue;
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}
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if (isdigit(word.start[0])) {
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exp->tag = SZEXP_CONST;
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if (bstr_sscanf(word, "%f", &exp->val.cval) != 1)
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return false;
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continue;
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}
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// Some sort of illegal expression
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return false;
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}
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return true;
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}
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// Returns whether successful. 'result' is left untouched on failure
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bool eval_szexpr(struct mp_log *log, void *priv,
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bool (*lookup)(void *priv, struct bstr var, float size[2]),
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struct szexp expr[MAX_SZEXP_SIZE], float *result)
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{
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float stack[MAX_SZEXP_SIZE] = {0};
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int idx = 0; // points to next element to push
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for (int i = 0; i < MAX_SZEXP_SIZE; i++) {
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switch (expr[i].tag) {
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case SZEXP_END:
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goto done;
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case SZEXP_CONST:
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// Since our SZEXPs are bound by MAX_SZEXP_SIZE, it should be
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// impossible to overflow the stack
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assert(idx < MAX_SZEXP_SIZE);
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stack[idx++] = expr[i].val.cval;
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continue;
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case SZEXP_OP1:
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if (idx < 1) {
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mp_warn(log, "Stack underflow in RPN expression!\n");
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return false;
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}
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switch (expr[i].val.op) {
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case SZEXP_OP_NOT: stack[idx-1] = !stack[idx-1]; break;
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default: abort();
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}
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continue;
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case SZEXP_OP2:
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if (idx < 2) {
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mp_warn(log, "Stack underflow in RPN expression!\n");
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return false;
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}
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// Pop the operands in reverse order
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float op2 = stack[--idx];
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float op1 = stack[--idx];
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float res = 0.0;
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switch (expr[i].val.op) {
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case SZEXP_OP_ADD: res = op1 + op2; break;
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case SZEXP_OP_SUB: res = op1 - op2; break;
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case SZEXP_OP_MUL: res = op1 * op2; break;
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case SZEXP_OP_DIV: res = op1 / op2; break;
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case SZEXP_OP_GT: res = op1 > op2; break;
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case SZEXP_OP_LT: res = op1 < op2; break;
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default: abort();
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}
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if (!isfinite(res)) {
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mp_warn(log, "Illegal operation in RPN expression!\n");
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return false;
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}
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stack[idx++] = res;
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continue;
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case SZEXP_VAR_W:
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case SZEXP_VAR_H: {
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struct bstr name = expr[i].val.varname;
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float size[2];
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if (!lookup(priv, name, size)) {
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mp_warn(log, "Variable %.*s not found in RPN expression!\n",
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BSTR_P(name));
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return false;
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}
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stack[idx++] = (expr[i].tag == SZEXP_VAR_W) ? size[0] : size[1];
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continue;
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}
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}
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}
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done:
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// Return the single stack element
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if (idx != 1) {
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mp_warn(log, "Malformed stack after RPN expression!\n");
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return false;
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}
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*result = stack[0];
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return true;
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}
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// Returns false if no more shaders could be parsed
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bool parse_user_shader_pass(struct mp_log *log, struct bstr *body,
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struct gl_user_shader *out)
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{
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if (!body || !out || !body->start || body->len == 0)
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return false;
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*out = (struct gl_user_shader){
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.offset = identity_trans,
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.width = {{ SZEXP_VAR_W, { .varname = bstr0("HOOKED") }}},
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.height = {{ SZEXP_VAR_H, { .varname = bstr0("HOOKED") }}},
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.cond = {{ SZEXP_CONST, { .cval = 1.0 }}},
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};
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int hook_idx = 0;
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int bind_idx = 0;
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// Skip all garbage (e.g. comments) before the first header
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int pos = bstr_find(*body, bstr0("//!"));
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if (pos < 0) {
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mp_warn(log, "Shader appears to contain no passes!\n");
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return false;
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}
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*body = bstr_cut(*body, pos);
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// First parse all the headers
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while (true) {
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struct bstr rest;
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struct bstr line = bstr_strip(bstr_getline(*body, &rest));
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// Check for the presence of the magic line beginning
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if (!bstr_eatstart0(&line, "//!"))
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break;
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*body = rest;
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// Parse the supported commands
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if (bstr_eatstart0(&line, "HOOK")) {
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if (hook_idx == SHADER_MAX_HOOKS) {
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mp_err(log, "Passes may only hook up to %d textures!\n",
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SHADER_MAX_HOOKS);
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return false;
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}
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out->hook_tex[hook_idx++] = bstr_strip(line);
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continue;
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}
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if (bstr_eatstart0(&line, "BIND")) {
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if (bind_idx == SHADER_MAX_BINDS) {
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mp_err(log, "Passes may only bind up to %d textures!\n",
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SHADER_MAX_BINDS);
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return false;
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}
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out->bind_tex[bind_idx++] = bstr_strip(line);
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continue;
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}
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if (bstr_eatstart0(&line, "SAVE")) {
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out->save_tex = bstr_strip(line);
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continue;
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}
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if (bstr_eatstart0(&line, "OFFSET")) {
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float ox, oy;
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if (bstr_sscanf(line, "%f %f", &ox, &oy) != 2) {
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mp_err(log, "Error while parsing OFFSET!\n");
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return false;
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}
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out->offset.t[0] = ox;
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out->offset.t[1] = oy;
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continue;
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}
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if (bstr_eatstart0(&line, "WIDTH")) {
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if (!parse_rpn_szexpr(line, out->width)) {
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mp_err(log, "Error while parsing WIDTH!\n");
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return false;
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}
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continue;
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}
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if (bstr_eatstart0(&line, "HEIGHT")) {
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if (!parse_rpn_szexpr(line, out->height)) {
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mp_err(log, "Error while parsing HEIGHT!\n");
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return false;
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}
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continue;
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}
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if (bstr_eatstart0(&line, "WHEN")) {
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if (!parse_rpn_szexpr(line, out->cond)) {
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mp_err(log, "Error while parsing WHEN!\n");
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return false;
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}
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continue;
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}
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if (bstr_eatstart0(&line, "COMPONENTS")) {
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if (bstr_sscanf(line, "%d", &out->components) != 1) {
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mp_err(log, "Error while parsing COMPONENTS!\n");
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return false;
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}
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continue;
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}
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// Unknown command type
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mp_err(log, "Unrecognized command '%.*s'!\n", BSTR_P(line));
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return false;
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}
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// The rest of the file up until the next magic line beginning (if any)
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// shall be the shader body
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if (bstr_split_tok(*body, "//!", &out->pass_body, body)) {
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// Make sure the magic line is part of the rest
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body->start -= 3;
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body->len += 3;
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}
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// Sanity checking
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if (hook_idx == 0)
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mp_warn(log, "Pass has no hooked textures (will be ignored)!\n");
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return true;
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}
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