Commit eba07020 authored by Neil Roberts's avatar Neil Roberts

cogl-gles2-wrapper: Add support for the layer combine operations

The texture layer combine functions are now hard coded to GL_COMBINE
instead of GL_MODULATE. The combine function can be customized with
all the parameters of GL_COMBINE. A shader is generated to implement
the given parameters.

Currently it will try to generate code for the constant color but it
will use a uniform which does not exist.
parent 02b95239
......@@ -172,15 +172,6 @@ validate_tex_combine_statements (CoglBlendStringStatement *statements,
for (i = 0; i < n_statements; i++)
{
#ifdef HAVE_COGL_GLES2
if (statements[i].function->type != COGL_BLEND_STRING_FUNCTION_MODULATE)
{
error_string = "Using anything but MODULATE() for texture combining"
" under GLES 2 is currently unsupported";
detail = COGL_BLEND_STRING_ERROR_GPU_UNSUPPORTED_ERROR;
goto error;
}
#endif
for (j = 0; j < statements[i].function->argc; j++)
{
CoglBlendStringArgument *arg = &statements[i].args[j];
......
......@@ -130,6 +130,31 @@ initialize_texture_units (CoglGles2Wrapper *w)
w->active_texture_unit = i;
GE( cogl_wrap_glMatrixMode (GL_TEXTURE));
GE( cogl_wrap_glLoadIdentity ());
/* The real GL default is GL_MODULATE but the shader only
supports GL_COMBINE so let's default to that instead */
GE( cogl_wrap_glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE,
GL_COMBINE) );
GE( cogl_wrap_glTexEnvi (GL_TEXTURE_ENV, GL_COMBINE_RGB,
GL_MODULATE) );
GE( cogl_wrap_glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_RGB,
GL_PREVIOUS) );
GE( cogl_wrap_glTexEnvi (GL_TEXTURE_ENV, GL_SRC1_RGB,
GL_TEXTURE) );
GE( cogl_wrap_glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_RGB,
GL_SRC_COLOR) );
GE( cogl_wrap_glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND1_RGB,
GL_SRC_COLOR) );
GE( cogl_wrap_glTexEnvi (GL_TEXTURE_ENV, GL_COMBINE_ALPHA,
GL_MODULATE) );
GE( cogl_wrap_glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_ALPHA,
GL_PREVIOUS) );
GE( cogl_wrap_glTexEnvi (GL_TEXTURE_ENV, GL_SRC1_ALPHA,
GL_TEXTURE) );
GE( cogl_wrap_glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_ALPHA,
GL_SRC_COLOR) );
GE( cogl_wrap_glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND1_ALPHA,
GL_SRC_COLOR) );
}
GE( cogl_wrap_glMatrixMode ((GLenum) prev_mode));
......@@ -172,12 +197,35 @@ cogl_gles2_wrapper_init (CoglGles2Wrapper *wrapper)
initialize_texture_units (wrapper);
}
static int
cogl_gles2_get_n_args_for_combine_func (GLenum func)
{
switch (func)
{
case GL_REPLACE:
return 1;
case GL_MODULATE:
case GL_ADD:
case GL_ADD_SIGNED:
case GL_SUBTRACT:
case GL_DOT3_RGB:
case GL_DOT3_RGBA:
return 2;
case GL_INTERPOLATE:
return 3;
default:
return 0;
}
}
static gboolean
cogl_gles2_settings_equal (const CoglGles2WrapperSettings *a,
const CoglGles2WrapperSettings *b,
gboolean vertex_tests,
gboolean fragment_tests)
{
int i;
if (a->texture_units != b->texture_units)
return FALSE;
......@@ -195,6 +243,34 @@ cogl_gles2_settings_equal (const CoglGles2WrapperSettings *a,
if (vertex_tests && a->fog_enabled && a->fog_mode != b->fog_mode)
return FALSE;
/* Compare layer combine operation for each active unit */
if (fragment_tests)
for (i = 0; i < COGL_GLES2_MAX_TEXTURE_UNITS; i++)
if (COGL_GLES2_TEXTURE_UNIT_IS_ENABLED (a->texture_units, i))
{
const CoglGles2WrapperTexEnv *tex_env_a = a->tex_env + i;
const CoglGles2WrapperTexEnv *tex_env_b = b->tex_env + i;
int arg, n_args;
GLenum func;
func = tex_env_a->texture_combine_rgb_func;
if (func != tex_env_b->texture_combine_rgb_func)
return FALSE;
n_args = cogl_gles2_get_n_args_for_combine_func (func);
for (arg = 0; arg < n_args; arg++)
{
if (tex_env_a->texture_combine_rgb_src[arg] !=
tex_env_b->texture_combine_rgb_src[arg])
return FALSE;
if (tex_env_a->texture_combine_rgb_op[arg] !=
tex_env_b->texture_combine_rgb_op[arg])
return FALSE;
}
}
return TRUE;
}
......@@ -307,6 +383,187 @@ cogl_gles2_get_vertex_shader (const CoglGles2WrapperSettings *settings)
return shader;
}
static void
cogl_gles2_add_arg (int unit,
GLenum src,
GLenum operand,
const char *swizzle,
GString *shader_source)
{
char alpha_swizzle[5] = "aaaa";
g_string_append_c (shader_source, '(');
if (operand == GL_ONE_MINUS_SRC_COLOR || operand == GL_ONE_MINUS_SRC_ALPHA)
g_string_append_printf (shader_source,
"vec4(1.0, 1.0, 1.0, 1.0).%s - ",
swizzle);
/* If the operand is reading from the alpha then replace the swizzle
with the same number of copies of the alpha */
if (operand == GL_SRC_ALPHA || operand == GL_ONE_MINUS_SRC_ALPHA)
{
alpha_swizzle[strlen (swizzle)] = '\0';
swizzle = alpha_swizzle;
}
switch (src)
{
case GL_TEXTURE:
g_string_append_printf (shader_source,
"texture2D (texture_unit[%d], tex_coord[%d]).%s",
unit, unit, swizzle);
break;
case GL_CONSTANT:
g_string_append_printf (shader_source, "combine_constant[%d].%s",
unit, swizzle);
break;
case GL_PREVIOUS:
if (unit > 0)
{
g_string_append_printf (shader_source, "gl_FragColor.%s", swizzle);
break;
}
/* flow through */
case GL_PRIMARY_COLOR:
g_string_append_printf (shader_source, "frag_color.%s", swizzle);
break;
default:
if (src >= GL_TEXTURE0 &&
src < GL_TEXTURE0 + COGL_GLES2_MAX_TEXTURE_UNITS)
g_string_append_printf (shader_source,
"texture2D (texture_unit[%d], "
"tex_coord[%d]).%s",
src - GL_TEXTURE0,
src - GL_TEXTURE0,
swizzle);
break;
}
g_string_append_c (shader_source, ')');
}
static void
cogl_gles2_add_operation (int unit,
GLenum combine_func,
const GLenum *sources,
const GLenum *operands,
const char *swizzle,
GString *shader_source)
{
switch (combine_func)
{
case GL_REPLACE:
cogl_gles2_add_arg (unit, sources[0], operands[0],
swizzle, shader_source);
break;
case GL_MODULATE:
cogl_gles2_add_arg (unit, sources[0], operands[0],
swizzle, shader_source);
g_string_append (shader_source, " * ");
cogl_gles2_add_arg (unit, sources[1], operands[1],
swizzle, shader_source);
break;
case GL_ADD:
cogl_gles2_add_arg (unit, sources[0], operands[0],
swizzle, shader_source);
g_string_append (shader_source, " + ");
cogl_gles2_add_arg (unit, sources[1], operands[1],
swizzle, shader_source);
break;
case GL_ADD_SIGNED:
cogl_gles2_add_arg (unit, sources[0], operands[0],
swizzle, shader_source);
g_string_append (shader_source, " + ");
cogl_gles2_add_arg (unit, sources[1], operands[1],
swizzle, shader_source);
g_string_append_printf (shader_source,
" - vec4(0.5, 0.5, 0.5, 0.5).%s",
swizzle);
break;
case GL_SUBTRACT:
cogl_gles2_add_arg (unit, sources[0], operands[0],
swizzle, shader_source);
g_string_append (shader_source, " - ");
cogl_gles2_add_arg (unit, sources[1], operands[1],
swizzle, shader_source);
break;
case GL_INTERPOLATE:
cogl_gles2_add_arg (unit, sources[0], operands[0],
swizzle, shader_source);
g_string_append (shader_source, " * ");
cogl_gles2_add_arg (unit, sources[2], operands[2],
swizzle, shader_source);
g_string_append (shader_source, " + ");
cogl_gles2_add_arg (unit, sources[1], operands[1],
swizzle, shader_source);
g_string_append_printf (shader_source,
" * (vec4(1.0, 1.0, 1.0, 1.0).%s - ",
swizzle);
cogl_gles2_add_arg (unit, sources[2], operands[2],
swizzle, shader_source);
g_string_append_c (shader_source, ')');
break;
case GL_DOT3_RGB:
case GL_DOT3_RGBA:
g_string_append (shader_source, "vec4(4 * ((");
cogl_gles2_add_arg (unit, sources[0], operands[0],
"r", shader_source);
g_string_append (shader_source, " - 0.5) * (");
cogl_gles2_add_arg (unit, sources[1], operands[1],
"r", shader_source);
g_string_append (shader_source, " - 0.5) + (");
cogl_gles2_add_arg (unit, sources[0], operands[0],
"g", shader_source);
g_string_append (shader_source, " - 0.5) * (");
cogl_gles2_add_arg (unit, sources[1], operands[1],
"g", shader_source);
g_string_append (shader_source, " - 0.5) + (");
cogl_gles2_add_arg (unit, sources[0], operands[0],
"b", shader_source);
g_string_append (shader_source, " - 0.5) * (");
cogl_gles2_add_arg (unit, sources[1], operands[1],
"b", shader_source);
g_string_append_printf (shader_source, " - 0.5))).%s", swizzle);
break;
}
}
static gboolean
cogl_gles2_rgb_and_alpha_equal (const CoglGles2WrapperTexEnv *tex_env)
{
int arg, n_args;
if (tex_env->texture_combine_rgb_func != tex_env->texture_combine_alpha_func)
return FALSE;
n_args =
cogl_gles2_get_n_args_for_combine_func (tex_env->texture_combine_rgb_func);
for (arg = 0; arg < n_args; arg++)
{
if (tex_env->texture_combine_rgb_src[arg] !=
tex_env->texture_combine_alpha_src[arg])
return FALSE;
if (tex_env->texture_combine_rgb_op[arg] != GL_SRC_COLOR ||
tex_env->texture_combine_alpha_op[arg] != GL_SRC_ALPHA)
return FALSE;
}
return TRUE;
}
static CoglGles2WrapperShader *
cogl_gles2_get_fragment_shader (const CoglGles2WrapperSettings *settings)
{
......@@ -359,29 +616,55 @@ cogl_gles2_get_fragment_shader (const CoglGles2WrapperSettings *settings)
apparent bug in the PowerVR drivers. Without it the alpha
blending seems to stop working */
g_string_append (shader_source,
"vec4 frag_color_copy = frag_color;\n");
g_string_append (shader_source, "gl_FragColor = frag_color;\n");
"vec4 frag_color_copy = frag_color;\n");
for (i = 0; i < n_texture_units; i++)
if (COGL_GLES2_TEXTURE_UNIT_IS_ENABLED (settings->texture_units, i))
{
if (COGL_GLES2_TEXTURE_UNIT_IS_ALPHA_ONLY (settings->texture_units, i))
/* If the texture only has an alpha channel (eg, with the textures
from the pango renderer) then the RGB components will be
black. We want to use the RGB from the current color in that
case */
g_string_append_printf (shader_source,
"gl_FragColor.a *= "
"texture2D (texture_unit[%d], "
"tex_coord[%d]).a;\n",
i, i);
else
g_string_append_printf (shader_source,
"gl_FragColor *= "
"texture2D (texture_unit[%d], "
"tex_coord[%d]);\n",
i, i);
}
/* If there are no textures units enabled then we can just directly
use the color from the vertex shader */
if (n_texture_units == 0)
g_string_append (shader_source, "gl_FragColor = frag_color;\n");
else
/* Otherwise we need to calculate the value based on the layer
combine settings */
for (i = 0; i < n_texture_units; i++)
if (COGL_GLES2_TEXTURE_UNIT_IS_ENABLED (settings->texture_units, i))
{
const CoglGles2WrapperTexEnv *tex_env = settings->tex_env + i;
/* If the rgb and alpha combine functions are the same then
we can do both with a single statement, otherwise we need
to do them separately */
if (cogl_gles2_rgb_and_alpha_equal (tex_env))
{
g_string_append (shader_source, "gl_FragColor.rgba = ");
cogl_gles2_add_operation (i,
tex_env->texture_combine_rgb_func,
tex_env->texture_combine_rgb_src,
tex_env->texture_combine_rgb_op,
"rgba",
shader_source);
g_string_append (shader_source, ";\n");
}
else
{
g_string_append (shader_source, "gl_FragColor.rgb = ");
cogl_gles2_add_operation (i,
tex_env->texture_combine_rgb_func,
tex_env->texture_combine_rgb_src,
tex_env->texture_combine_rgb_op,
"rgb",
shader_source);
g_string_append (shader_source,
";\n"
"gl_FragColor.a = ");
cogl_gles2_add_operation (i,
tex_env->texture_combine_alpha_func,
tex_env->texture_combine_alpha_src,
tex_env->texture_combine_alpha_op,
"a",
shader_source);
g_string_append (shader_source, ";\n");
}
}
if (settings->fog_enabled)
g_string_append (shader_source, cogl_fixed_fragment_shader_fog);
......@@ -1079,16 +1362,61 @@ cogl_gles2_wrapper_bind_texture (GLenum target, GLuint texture,
void
cogl_wrap_glTexEnvi (GLenum target, GLenum pname, GLint param)
{
/* This function is only used to set the texture mode once to
GL_MODULATE. The shader is hard-coded to modulate the texture so
nothing needs to be done here. */
if (target == GL_TEXTURE_ENV)
{
CoglGles2WrapperTexEnv *tex_env;
_COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);
tex_env = w->settings.tex_env + w->active_texture_unit;
switch (pname)
{
case GL_COMBINE_RGB:
tex_env->texture_combine_rgb_func = param;
break;
case GL_COMBINE_ALPHA:
tex_env->texture_combine_alpha_func = param;
break;
case GL_SRC0_RGB:
case GL_SRC1_RGB:
case GL_SRC2_RGB:
tex_env->texture_combine_rgb_src[pname - GL_SRC0_RGB] = param;
break;
case GL_SRC0_ALPHA:
case GL_SRC1_ALPHA:
case GL_SRC2_ALPHA:
tex_env->texture_combine_alpha_src[pname - GL_SRC0_ALPHA] = param;
break;
case GL_OPERAND0_RGB:
case GL_OPERAND1_RGB:
case GL_OPERAND2_RGB:
tex_env->texture_combine_rgb_op[pname - GL_OPERAND0_RGB] = param;
break;
case GL_OPERAND0_ALPHA:
case GL_OPERAND1_ALPHA:
case GL_OPERAND2_ALPHA:
tex_env->texture_combine_alpha_op[pname - GL_OPERAND0_ALPHA] = param;
break;
}
w->settings_dirty = TRUE;
}
}
void
cogl_wrap_glTexEnvfv (GLenum target, GLenum pname, const GLfloat *params)
{
/* FIXME: Currently needed to support texture combining using
* COGL_BLEND_STRING_COLOR_SOURCE_CONSTANT */
if (target == GL_TEXTURE_ENV && pname == GL_TEXTURE_ENV_COLOR)
{
CoglGles2WrapperTexEnv *tex_env;
_COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);
tex_env = w->settings.tex_env + w->active_texture_unit;
memcpy (tex_env->texture_combine_constant, params, sizeof (GLfloat) * 4);
}
}
void
......
......@@ -37,6 +37,7 @@ typedef struct _CoglGles2WrapperTextureUnit
typedef struct _CoglGles2WrapperAttributes CoglGles2WrapperAttributes;
typedef struct _CoglGles2WrapperUniforms CoglGles2WrapperUniforms;
typedef struct _CoglGles2WrapperTexEnv CoglGles2WrapperTexEnv;
typedef struct _CoglGles2WrapperTextureUnitSettings
CoglGles2WrapperTextureUnitSettings;
typedef struct _CoglGles2WrapperSettings CoglGles2WrapperSettings;
......@@ -115,6 +116,19 @@ struct _CoglGles2WrapperUniforms
GLint texture_unit_uniform;
};
struct _CoglGles2WrapperTexEnv
{
GLenum texture_combine_rgb_func;
GLenum texture_combine_rgb_src[3];
GLenum texture_combine_rgb_op[3];
GLenum texture_combine_alpha_func;
GLenum texture_combine_alpha_src[3];
GLenum texture_combine_alpha_op[3];
GLfloat texture_combine_constant[4];
};
/* NB: We get a copy of this for each fragment/vertex
* program varient we generate so we try to keep it
* fairly lean */
......@@ -130,6 +144,8 @@ struct _CoglGles2WrapperSettings
unsigned int alpha_test_enabled:1;
unsigned int fog_enabled:1;
CoglGles2WrapperTexEnv tex_env[COGL_GLES2_MAX_TEXTURE_UNITS];
};
struct _CoglGles2WrapperTextureUnit
......
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