0029283: Visualization - allow defining more than 8 light sources

OpenGl_ShaderManager now overrides THE_MAX_LIGHTS within built-in shading programs
so that maximum number of lights is now limited only by OpenGL hardware
(e.g. length of GLSL program, number of defined uniforms, result performance, etc.).
THE_MAX_CLIP_PLANES is now also defined by OpenGl_ShaderManager,
so that unused lights and clipping planes do not reserve extra uniforms in GLSL programs.

V3d_View::SetLightOn() does not throw exception anymore, when the number of lights exceeds 8.
Instead, OpenGl_ShaderManager::PushLightSourceState() emits warning
in case of usage of FFP providing consistent behavior with Clipping Planes number limit.

src/Shaders/Declarations.glsl

@@ -13,10 +13,16 @@
 // Alternatively, this file may be used under the terms of Open CASCADE
 // commercial license or contractual agreement.
 
-// This files includes definition of common uniform variables in OCCT GLSL programs
+//! @file Declarations.glsl
+//! This files includes definition of common uniform variables in OCCT GLSL programs
 
-#define THE_MAX_LIGHTS      8
-#define THE_MAX_CLIP_PLANES 8
+//! @def THE_MAX_LIGHTS
+//! Specifies the length of array of lights, which is 8 by default. Defined by Shader Manager.
+// #define THE_MAX_LIGHTS 8
+
+//! @def THE_MAX_CLIP_PLANES
+//! Specifies the length of array of clipping planes, which is 8 by default. Defined by Shader Manager.
+// #define THE_MAX_CLIP_PLANES 8
 
 // compatibility macros
 #if (__VERSION__ >= 130)
@@ -92,6 +98,7 @@ const int OccLightType_Spot   = 3; //!< spot            light source
 
 // Light sources
 uniform               vec4 occLightAmbient;      //!< Cumulative ambient color
+#if defined(THE_MAX_LIGHTS) && (THE_MAX_LIGHTS > 0)
 uniform THE_PREC_ENUM int  occLightSourcesCount; //!< Total number of light sources
 int   occLight_Type              (in int theId); //!< Type of light source
 int   occLight_IsHeadlight       (in int theId); //!< Is light a headlight?
@@ -103,6 +110,7 @@ float occLight_ConstAttenuation  (in int theId); //!< Const attenuation factor o
 float occLight_LinearAttenuation (in int theId); //!< Linear attenuation factor of positional light source
 float occLight_SpotCutOff        (in int theId); //!< Maximum spread angle of the spot light (in radians)
 float occLight_SpotExponent      (in int theId); //!< Attenuation of the spot light intensity (from 0 to 1)
+#endif
 
 // Front material properties accessors
 vec4  occFrontMaterial_Emission(void);     //!< Emission color
@@ -135,5 +143,7 @@ uniform               int       occOitOutput;      //!< Enable bit for writing o
 uniform               float     occOitDepthFactor; //!< Influence of the depth component to the coverage of the accumulated fragment
 
 //! Parameters of clipping planes
+#if defined(THE_MAX_CLIP_PLANES) && (THE_MAX_CLIP_PLANES > 0)
 uniform               vec4 occClipPlaneEquations[THE_MAX_CLIP_PLANES];
 uniform THE_PREC_ENUM int  occClipPlaneCount;   //!< Total number of clip planes
+#endif

src/Shaders/DeclarationsImpl.glsl

@@ -15,6 +15,7 @@
 
 // This file includes implementation of common functions and properties accessors
 
+#if defined(THE_MAX_LIGHTS) && (THE_MAX_LIGHTS > 0)
 // arrays of light sources
 uniform THE_PREC_ENUM ivec2 occLightSourcesTypes[THE_MAX_LIGHTS]; //!< packed light sources types
 uniform               vec4  occLightSources[THE_MAX_LIGHTS * 4];  //!< packed light sources parameters
@@ -30,6 +31,7 @@ float occLight_ConstAttenuation  (in int theId) { return occLightSources[theId *
 float occLight_LinearAttenuation (in int theId) { return occLightSources[theId * 4 + 3].y; }
 float occLight_SpotCutOff        (in int theId) { return occLightSources[theId * 4 + 3].z; }
 float occLight_SpotExponent      (in int theId) { return occLightSources[theId * 4 + 3].w; }
+#endif
 
 // material state
 uniform vec4 occFrontMaterial[5];

src/Shaders/Shaders_DeclarationsImpl_glsl.pxx

@@ -18,6 +18,7 @@ static const char Shaders_DeclarationsImpl_glsl[] =
   "\n"
   "// This file includes implementation of common functions and properties accessors\n"
   "\n"
+  "#if defined(THE_MAX_LIGHTS) && (THE_MAX_LIGHTS > 0)\n"
   "// arrays of light sources\n"
   "uniform THE_PREC_ENUM ivec2 occLightSourcesTypes[THE_MAX_LIGHTS]; //!< packed light sources types\n"
   "uniform               vec4  occLightSources[THE_MAX_LIGHTS * 4];  //!< packed light sources parameters\n"
@@ -33,6 +34,7 @@ static const char Shaders_DeclarationsImpl_glsl[] =
   "float occLight_LinearAttenuation (in int theId) { return occLightSources[theId * 4 + 3].y; }\n"
   "float occLight_SpotCutOff        (in int theId) { return occLightSources[theId * 4 + 3].z; }\n"
   "float occLight_SpotExponent      (in int theId) { return occLightSources[theId * 4 + 3].w; }\n"
+  "#endif\n"
   "\n"
   "// material state\n"
   "uniform vec4 occFrontMaterial[5];\n"

src/Shaders/Shaders_Declarations_glsl.pxx

@@ -16,10 +16,16 @@ static const char Shaders_Declarations_glsl[] =
   "// Alternatively, this file may be used under the terms of Open CASCADE\n"
   "// commercial license or contractual agreement.\n"
   "\n"
-  "// This files includes definition of common uniform variables in OCCT GLSL programs\n"
+  "//! @file Declarations.glsl\n"
+  "//! This files includes definition of common uniform variables in OCCT GLSL programs\n"
   "\n"
-  "#define THE_MAX_LIGHTS      8\n"
-  "#define THE_MAX_CLIP_PLANES 8\n"
+  "//! @def THE_MAX_LIGHTS\n"
+  "//! Specifies the length of array of lights, which is 8 by default. Defined by Shader Manager.\n"
+  "// #define THE_MAX_LIGHTS 8\n"
+  "\n"
+  "//! @def THE_MAX_CLIP_PLANES\n"
+  "//! Specifies the length of array of clipping planes, which is 8 by default. Defined by Shader Manager.\n"
+  "// #define THE_MAX_CLIP_PLANES 8\n"
   "\n"
   "// compatibility macros\n"
   "#if (__VERSION__ >= 130)\n"
@@ -95,6 +101,7 @@ static const char Shaders_Declarations_glsl[] =
   "\n"
   "// Light sources\n"
   "uniform               vec4 occLightAmbient;      //!< Cumulative ambient color\n"
+  "#if defined(THE_MAX_LIGHTS) && (THE_MAX_LIGHTS > 0)\n"
   "uniform THE_PREC_ENUM int  occLightSourcesCount; //!< Total number of light sources\n"
   "int   occLight_Type              (in int theId); //!< Type of light source\n"
   "int   occLight_IsHeadlight       (in int theId); //!< Is light a headlight?\n"
@@ -106,6 +113,7 @@ static const char Shaders_Declarations_glsl[] =
   "float occLight_LinearAttenuation (in int theId); //!< Linear attenuation factor of positional light source\n"
   "float occLight_SpotCutOff        (in int theId); //!< Maximum spread angle of the spot light (in radians)\n"
   "float occLight_SpotExponent      (in int theId); //!< Attenuation of the spot light intensity (from 0 to 1)\n"
+  "#endif\n"
   "\n"
   "// Front material properties accessors\n"
   "vec4  occFrontMaterial_Emission(void);     //!< Emission color\n"
@@ -138,5 +146,7 @@ static const char Shaders_Declarations_glsl[] =
   "uniform               float     occOitDepthFactor; //!< Influence of the depth component to the coverage of the accumulated fragment\n"
   "\n"
   "//! Parameters of clipping planes\n"
+  "#if defined(THE_MAX_CLIP_PLANES) && (THE_MAX_CLIP_PLANES > 0)\n"
   "uniform               vec4 occClipPlaneEquations[THE_MAX_CLIP_PLANES];\n"
-  "uniform THE_PREC_ENUM int  occClipPlaneCount;   //!< Total number of clip planes\n";
+  "uniform THE_PREC_ENUM int  occClipPlaneCount;   //!< Total number of clip planes\n"
+  "#endif\n";