mpv/video/out/opengl/user_shaders.c

285 lines
8.7 KiB
C

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