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authorMichal Krol <mjkrol@gmail.org>2006-02-13 11:42:48 +0000
committerMichal Krol <mjkrol@gmail.org>2006-02-13 11:42:48 +0000
commitebcbf2f8535491e1ff30859263df30d5615a4bfa (patch)
treef89aa84ce4a629d772a92014df31889d3baea749 /src/mesa/shader/slang/library/slang_fragment_builtin.gc
parent41eeae5fb1131b18b89b80e3e1a1f0e69b26c0ca (diff)
Cosmetic changes.
Diffstat (limited to 'src/mesa/shader/slang/library/slang_fragment_builtin.gc')
-rwxr-xr-xsrc/mesa/shader/slang/library/slang_fragment_builtin.gc389
1 files changed, 93 insertions, 296 deletions
diff --git a/src/mesa/shader/slang/library/slang_fragment_builtin.gc b/src/mesa/shader/slang/library/slang_fragment_builtin.gc
index b4c5aa3ec2..adfdaae8df 100755
--- a/src/mesa/shader/slang/library/slang_fragment_builtin.gc
+++ b/src/mesa/shader/slang/library/slang_fragment_builtin.gc
@@ -1,72 +1,14 @@
-//
+//
// TODO:
// - implement texture1D, texture2D, texture3D, textureCube,
// - implement shadow1D, shadow2D,
// - implement dFdx, dFdy,
-//
-
-//
-// From Shader Spec, ver. 1.10, rev. 59
-//
-// The output of the fragment shader is processed by the fixed function operations at the back end
-// of the OpenGL pipeline. Fragment shaders output values to the OpenGL pipeline using the built-in
-// variables gl_FragColor, gl_FragData and gl_FragDepth, unless the discard keyword is executed.
-//
-// These variables may be written more than once within a fragment shader. If so, the last value
-// assigned is the one used in the subsequent fixed function pipeline. The values written to these
-// variables may be read back after writing them. Reading from these variables before writing them
-// results in an undefined value. The fixed functionality computed depth for a fragment may be
-// obtained by reading gl_FragCoord.z, described below.
-//
-// Writing to gl_FragColor specifies the fragment color that will be used by the subsequent fixed
-// functionality pipeline. If subsequent fixed functionality consumes fragment color and an
-// execution of a fragment shader does not write a value to gl_FragColor then the fragment color
-// consumed is undefined.
-//
-// If the frame buffer is configured as a color index buffer then behavior is undefined when using
-// a fragment shader.
-//
-// Writing to gl_FragDepth will establish the depth value for the fragment being processed. If
-// depth buffering is enabled, and a shader does not write gl_FragDepth, then the fixed function
-// value for depth will be used as the fragment's depth value. If a shader statically assigns
-// a value to gl_FragDepth, and there is an execution path through the shader that does not set
-// gl_FragDepth, then the value of the fragment's depth may be undefined for executions of the
-// shader that take that path. That is, if a shader statically contains a write gl_FragDepth, then
-// it is responsible for always writing it.
//
-// (A shader contains a static assignment to a variable x if, after pre-processing, the shader
-// contains statement that would write x, whether or not run-time flow of control will cause
-// that statement to be executed.)
+
//
-// The variable gl_FragData is an array. Writing to gl_FragData[n] specifies the fragment data
-// that will be used by the subsequent fixed functionality pipeline for data n. If subsequent
-// fixed functionality consumes fragment data and an execution of a fragment shader does not
-// write a value to it, then the fragment data consumed is undefined.
+// From Shader Spec, ver. 1.10, rev. 59
//
-// If a shader statically assigns a value to gl_FragColor, it may not assign a value to any element
-// of gl_FragData. If a shader statically writes a value to any element of gl_FragData, it may not
-// assign a value to gl_FragColor. That is, a shader may assign values to either gl_FragColor or
-// gl_FragData, but not both.
-//
-// If a shader executes the discard keyword, the fragment is discarded, and the values of
-// gl_FragDepth, gl_FragColor and gl_FragData become irrelevant.
-//
-// The variable gl_FragCoord is available as a read-only variable from within fragment shaders
-// and it holds the window relative coordinates x, y, z, and 1/w values for the fragment. This
-// value is the result of the fixed functionality that interpolates primitives after vertex
-// processing to generate fragments. The z component is the depth value that would be used for
-// the fragment's depth if a shader contained no writes to gl_FragDepth. This is useful for
-// invariance if a shader conditionally computes gl_FragDepth but otherwise wants the fixed
-// functionality fragment depth.
-//
-// The fragment shader has access to the read-only built-in variable gl_FrontFacing whose value
-// is true if the fragment belongs to a front-facing primitive. One use of this is to emulate
-// two-sided lighting by selecting one of two colors calculated by the vertex shader.
-//
-// The built-in variables that are accessible from a fragment shader are intrinsically given types
-// as follows:
-//
__fixed_input vec4 gl_FragCoord;
__fixed_input bool gl_FrontFacing;
@@ -74,292 +16,147 @@ __fixed_output vec4 gl_FragColor;
__fixed_output vec4 gl_FragData[gl_MaxDrawBuffers];
__fixed_output float gl_FragDepth;
-//
-// However, they do not behave like variables with no qualifier; their behavior is as described
-// above. These built-in variables have global scope.
-//
-
-//
-// Unlike user-defined varying variables, the built-in varying variables don't have a strict
-// one-to-one correspondence between the vertex language and the fragment language. Two sets are
-// provided, one for each language. Their relationship is described below.
-//
-// The following varying variables are available to read from in a fragment shader. The gl_Color
-// and gl_SecondaryColor names are the same names as attributes passed to the vertex shader.
-// However, there is no name conflict, because attributes are visible only in vertex shaders
-// and the following are only visible in a fragment shader.
-//
-
varying vec4 gl_Color;
varying vec4 gl_SecondaryColor;
-varying vec4 gl_TexCoord[]; // at most will be gl_MaxTextureCoords
+varying vec4 gl_TexCoord[gl_MaxTextureCoords];
varying float gl_FogFragCoord;
-//
-// The values in gl_Color and gl_SecondaryColor will be derived automatically by the system from
-// gl_FrontColor, gl_BackColor, gl_FrontSecondaryColor, and gl_BackSecondaryColor based on which
-// face is visible. If fixed functionality is used for vertex processing, then gl_FogFragCoord will
-// either be the z-coordinate of the fragment in eye space, or the interpolation of the fog
-// coordinate, as described in section 3.10 of the OpenGL 1.4 Specification. The gl_TexCoord[]
-// values are the interpolated gl_TexCoord[] values from a vertex shader or the texture coordinates
-// of any fixed pipeline based vertex functionality.
-//
-// Indices to the fragment shader gl_TexCoord array are as described above in the vertex shader
-// text.
-//
-
-//
-// The OpenGL Shading Language defines an assortment of built-in convenience functions for scalar
-// and vector operations. Many of these built-in functions can be used in more than one type
-// of shader, but some are intended to provide a direct mapping to hardware and so are available
-// only for a specific type of shader.
-//
-// The built-in functions basically fall into three categories:
-//
-// * They expose some necessary hardware functionality in a convenient way such as accessing
-// a texture map. There is no way in the language for these functions to be emulated by a shader.
-//
-// * They represent a trivial operation (clamp, mix, etc.) that is very simple for the user
-// to write, but they are very common and may have direct hardware support. It is a very hard
-// problem for the compiler to map expressions to complex assembler instructions.
-//
-// * They represent an operation graphics hardware is likely to accelerate at some point. The
-// trigonometry functions fall into this category.
-//
-// Many of the functions are similar to the same named ones in common C libraries, but they support
-// vector input as well as the more traditional scalar input.
-//
-// Applications should be encouraged to use the built-in functions rather than do the equivalent
-// computations in their own shader code since the built-in functions are assumed to be optimal
-// (e.g., perhaps supported directly in hardware).
-//
-// User code can replace built-in functions with their own if they choose, by simply re-declaring
-// and defining the same name and argument list.
-//
-
-//
+//
// 8.7 Texture Lookup Functions
-//
-// Texture lookup functions are available to both vertex and fragment shaders. However, level
-// of detail is not computed by fixed functionality for vertex shaders, so there are some
-// differences in operation between vertex and fragment texture lookups. The functions in the table
-// below provide access to textures through samplers, as set up through the OpenGL API. Texture
-// properties such as size, pixel format, number of dimensions, filtering method, number of mip-map
-// levels, depth comparison, and so on are also defined by OpenGL API calls. Such properties are
-// taken into account as the texture is accessed via the built-in functions defined below.
-//
-// If a non-shadow texture call is made to a sampler that represents a depth texture with depth
-// comparisons turned on, then results are undefined. If a shadow texture call is made to a sampler
-// that represents a depth texture with depth comparisions turned off, the results are undefined.
-// If a shadow texture call is made to a sampler that does not represent a depth texture, then
-// results are undefined.
-//
-// In all functions below, the bias parameter is optional for fragment shaders. The bias parameter
-// is not accepted in a vertex shader. For a fragment shader, if bias is present, it is added to
-// the calculated level of detail prior to performing the texture access operation. If the bias
-// parameter is not provided, then the implementation automatically selects level of detail:
-// For a texture that is not mip-mapped, the texture is used directly. If it is mip-mapped and
-// running in a fragment shader, the LOD computed by the implementation is used to do the texture
-// lookup. If it is mip-mapped and running on the vertex shader, then the base texture is used.
-//
-// The built-ins suffixed with "Lod" are allowed only in a vertex shader. For the "Lod" functions,
-// lod is directly used as the level of detail.
-//
-
-//
-// Use the texture coordinate coord to do a texture lookup in the 1D texture currently bound
-// to sampler. For the projective ("Proj") versions, the texture coordinate coord.s is divided by
-// the last component of coord.
-//
-// XXX
-vec4 texture1D (sampler1D sampler, float coord, float bias) {
+//
+
+vec4 texture1D (sampler1D sampler, float coord, float bias) {
+ // XXX:
return vec4 (0.0);
-}
+}
+
vec4 texture1DProj (sampler1D sampler, vec2 coord, float bias) {
return texture1D (sampler, coord.s / coord.t, bias);
-}
+}
+
vec4 texture1DProj (sampler1D sampler, vec4 coord, float bias) {
return texture1D (sampler, coord.s / coord.q, bias);
}
-//
-// Use the texture coordinate coord to do a texture lookup in the 2D texture currently bound
-// to sampler. For the projective ("Proj") versions, the texture coordinate (coord.s, coord.t) is
-// divided by the last component of coord. The third component of coord is ignored for the vec4
-// coord variant.
-//
-// XXX
-vec4 texture2D (sampler2D sampler, vec2 coord, float bias) {
+vec4 texture2D (sampler2D sampler, vec2 coord, float bias) {
+ // XXX:
return vec4 (0.0);
-}
-vec4 texture2DProj (sampler2D sampler, vec3 coord, float bias) {
- return texture2D (sampler, vec2 (coord.s / coord.p, coord.t / coord.p), bias);
-}
-vec4 texture2DProj (sampler2D sampler, vec4 coord, float bias) {
- return texture2D (sampler, vec2 (coord.s / coord.q, coord.s / coord.q), bias);
+}
+
+vec4 texture2DProj (sampler2D sampler, vec3 coord, float bias) {
+ vec2 u;
+ u.s = coord.s / coord.p;
+ u.t = coord.t / coord.p;
+ return texture2D (sampler, u, bias);
+}
+
+vec4 texture2DProj (sampler2D sampler, vec4 coord, float bias) {
+ vec2 u;
+ u.s = coord.s / coord.q;
+ u.t = coord.t / coord.q;
+ return texture2D (sampler, u, bias);
}
-//
-// Use the texture coordinate coord to do a texture lookup in the 3D texture currently bound
-// to sampler. For the projective ("Proj") versions, the texture coordinate is divided by coord.q.
-//
-// XXX
-vec4 texture3D (sampler3D sampler, vec3 coord, float bias) {
+vec4 texture3D (sampler3D sampler, vec3 coord, float bias) {
+ // XXX:
return vec4 (0.0);
-}
-vec4 texture3DProj (sampler3D sampler, vec4 coord, float bias) {
- return texture3DProj (sampler, vec3 (coord.s / coord.q, coord.t / coord.q, coord.p / coord.q),
- bias);
+}
+
+vec4 texture3DProj (sampler3D sampler, vec4 coord, float bias) {
+ vec3 u;
+ u.s = coord.s / coord.q;
+ u.t = coord.t / coord.q;
+ u.p = coord.p / coord.q;
+ return texture3D (sampler, u, bias);
}
-//
-// Use the texture coordinate coord to do a texture lookup in the cube map texture currently bound
-// to sampler. The direction of coord is used to select which face to do a 2-dimensional texture
-// lookup in, as described in section 3.8.6 in version 1.4 of the OpenGL specification.
-//
-// XXX
-vec4 textureCube (samplerCube sampler, vec3 coord, float bias) {
+vec4 textureCube (samplerCube sampler, vec3 coord, float bias) {
+ // XXX:
return vec4 (0.0);
}
-//
-// Use texture coordinate coord to do a depth comparison lookup on the depth texture bound
-// to sampler, as described in section 3.8.14 of version 1.4 of the OpenGL specification. The 3rd
-// component of coord (coord.p) is used as the R value. The texture bound to sampler must be a
-// depth texture, or results are undefined. For the projective ("Proj") version of each built-in,
-// the texture coordinate is divide by coord.q, giving a depth value R of coord.p/coord.q. The
-// second component of coord is ignored for the "1D" variants.
-//
-// XXX
-vec4 shadow1D (sampler1DShadow sampler, vec3 coord, float bias) {
+vec4 shadow1D (sampler1DShadow sampler, vec3 coord, float bias) {
+ // XXX:
return vec4 (0.0);
-}
-// XXX
-vec4 shadow2D (sampler2DShadow sampler, vec3 coord, float bias) {
+}
+
+vec4 shadow2D (sampler2DShadow sampler, vec3 coord, float bias) {
+ // XXX:
return vec4 (0.0);
-}
-vec4 shadow1DProj (sampler1DShadow sampler, vec4 coord, float bias) {
- return shadow1D (sampler, vec3 (coord.s / coord.q, 0.0, coord.p / coord.q), bias);
-}
-vec4 shadow2DProj (sampler2DShadow sampler, vec4 coord, float bias) {
- return shadow2D (sampler, vec3 (coord.s / coord.q, coord.t / coord.q, coord.p / coord.q), bias);
+}
+
+vec4 shadow1DProj (sampler1DShadow sampler, vec4 coord, float bias) {
+ vec3 u;
+ u.s = coord.s / coord.q;
+ u.t = 0.0;
+ u.p = coord.p / coord.q;
+ return shadow1D (sampler, u, bias);
+}
+
+vec4 shadow2DProj (sampler2DShadow sampler, vec4 coord, float bias) {
+ vec3 u;
+ u.s = coord.s / coord.q;
+ u.t = coord.t / coord.q;
+ u.p = coord.p / coord.q;
+ return shadow2D (sampler, u, bias);
}
//
// 8.8 Fragment Processing Functions
-//
-// Fragment processing functions are only available in shaders intended for use on the fragment
-// processor. Derivatives may be computationally expensive and/or numerically unstable. Therefore,
-// an OpenGL implementation may approximate the true derivatives by using a fast but not entirely
-// accurate derivative computation.
-//
-// The expected behavior of a derivative is specified using forward/backward differencing.
-//
-// Forward differencing:
-//
-// F(x+dx) - F(x) ~ dFdx(x) * dx 1a
-// dFdx(x) ~ (F(x+dx) - F(x)) / dx 1b
-//
-// Backward differencing:
-//
-// F(x-dx) - F(x) ~ -dFdx(x) * dx 2a
-// dFdx(x) ~ (F(x) - F(x-dx)) / dx 2b
-//
-// With single-sample rasterization, dx <= 1.0 in equations 1b and 2b. For multi-sample
-// rasterization, dx < 2.0 in equations 1b and 2b.
-//
-// dFdy is approximated similarly, with y replacing x.
-//
-// A GL implementation may use the above or other methods to perform the calculation, subject
-// to the following conditions:
-//
-// 1) The method may use piecewise linear approximations. Such linear approximations imply that
-// higher order derivatives, dFdx(dFdx(x)) and above, are undefined.
-//
-// 2) The method may assume that the function evaluated is continuous. Therefore derivatives within
-// the body of a non-uniform conditional are undefined.
-//
-// 3) The method may differ per fragment, subject to the constraint that the method may vary by
-// window coordinates, not screen coordinates. The invariance requirement described in section
-// 3.1 of the OpenGL 1.4 specification is relaxed for derivative calculations, because
-// the method may be a function of fragment location.
-//
-// Other properties that are desirable, but not required, are:
-//
-// 4) Functions should be evaluated within the interior of a primitive (interpolated, not
-// extrapolated).
-//
-// 5) Functions for dFdx should be evaluated while holding y constant. Functions for dFdy should
-// be evaluated while holding x constant. However, mixed higher order derivatives, like
-// dFdx(dFdy(y)) and dFdy(dFdx(x)) are undefined.
-//
-// In some implementations, varying degrees of derivative accuracy may be obtained by providing
-// GL hints (section 5.6 of the OpenGL 1.4 specification), allowing a user to make an image
-// quality versus speed tradeoff.
-//
-
-//
-// Returns the derivative in x using local differencing for the input argument p.
-//
-// XXX
-float dFdx (float p) {
+//
+
+float dFdx (float p) {
+ // XXX:
return 0.0;
}
-// XXX
-vec2 dFdx (vec2 p) {
+
+vec2 dFdx (vec2 p) {
+ // XXX:
return vec2 (0.0);
}
-// XXX
-vec3 dFdx (vec3 p) {
+
+vec3 dFdx (vec3 p) {
+ // XXX:
return vec3 (0.0);
}
-// XXX
-vec4 dFdx (vec4 p) {
+
+vec4 dFdx (vec4 p) {
+ // XXX:
return vec4 (0.0);
}
-//
-// Returns the derivative in y using local differencing for the input argument p.
-//
-// These two functions are commonly used to estimate the filter width used to anti-alias procedural
-// textures.We are assuming that the expression is being evaluated in parallel on a SIMD array so
-// that at any given point in time the value of the function is known at the grid points
-// represented by the SIMD array. Local differencing between SIMD array elements can therefore
-// be used to derive dFdx, dFdy, etc.
-//
-// XXX
-float dFdy (float p) {
+float dFdy (float p) {
+ // XXX:
return 0.0;
}
-// XXX
-vec2 dFdy (vec2 p) {
+
+vec2 dFdy (vec2 p) {
+ // XXX:
return vec2 (0.0);
}
-// XXX
-vec3 dFdy (vec3 p) {
+
+vec3 dFdy (vec3 p) {
+ // XXX:
return vec3 (0.0);
}
-// XXX
-vec4 dFdy (vec4 p) {
+
+vec4 dFdy (vec4 p) {
+ // XXX:
return vec4 (0.0);
}
-//
-// Returns the sum of the absolute derivative in x and y using local differencing for the input
-// argument p, i.e.:
-//
-// return = abs (dFdx (p)) + abs (dFdy (p));
-//
-
float fwidth (float p) {
return abs (dFdx (p)) + abs (dFdy (p));
-}
+}
+
vec2 fwidth (vec2 p) {
return abs (dFdx (p)) + abs (dFdy (p));
-}
+}
+
vec3 fwidth (vec3 p) {
return abs (dFdx (p)) + abs (dFdy (p));
-}
+}
+
vec4 fwidth (vec4 p) {
return abs (dFdx (p)) + abs (dFdy (p));
}