Merge pull request #1327 from asarium/fix/1326

Apply clipping planes to passthrough shader

Author: niffiwan

.editorconfig

@@ -2,3 +2,6 @@ root = true
 
 [*.{h,cpp}]
 indent_style = tab
+
+[*.sdr]
+indent_style = tab

code/def_files/passthrough-v.sdr

@@ -6,9 +6,18 @@ out vec4 fragColor;
 uniform mat4 modelViewMatrix;
 uniform mat4 projMatrix;
 uniform vec4 color;
+
+uniform mat4 modelMatrix;
+uniform bool clipEnabled;
+uniform vec4 clipEquation;
+
 void main()
 {
 	fragTexCoord = vertTexCoord;
 	fragColor = vertColor * color;
 	gl_Position = projMatrix * modelViewMatrix * vertPosition;
-}
+
+	if (clipEnabled) {
+		gl_ClipDistance[0] = dot(clipEquation, modelMatrix * vertPosition);
+	}
+}

code/graphics/opengl/gropenglshader.cpp

@@ -106,7 +106,7 @@ static opengl_shader_type_t GL_shader_types[] = {
 		{ opengl_vert_attrib::POSITION, opengl_vert_attrib::TEXCOORD }, "Video Playback" },
 
 	{ SDR_TYPE_PASSTHROUGH_RENDER, "passthrough-v.sdr", "passthrough-f.sdr", 0,
-		{ "modelViewMatrix", "projMatrix", "baseMap", "noTexturing", "alphaTexture", "srgb", "intensity", "color", "alphaThreshold" },
+		{ "modelViewMatrix", "projMatrix", "baseMap", "noTexturing", "alphaTexture", "srgb", "intensity", "color", "alphaThreshold", "clipEnabled", "clipEquation", "modelMatrix" },
 		{ opengl_vert_attrib::POSITION, opengl_vert_attrib::TEXCOORD, opengl_vert_attrib::COLOR }, "Passthrough" },
 
 	{ SDR_TYPE_SHIELD_DECAL, "shield-impact-v.sdr",	"shield-impact-f.sdr", 0,
@@ -788,7 +788,7 @@ void opengl_shader_compile_passthrough_shader()
 	opengl_shader_set_current();
 }
 
-void opengl_shader_set_passthrough(bool textured, bool alpha, vec4 *clr, float color_scale)
+void opengl_shader_set_passthrough(bool textured, bool alpha, vec4 *clr, float color_scale, const material::clip_plane& clip_plane)
 {
 	opengl_shader_set_current(gr_opengl_maybe_create_shader(SDR_TYPE_PASSTHROUGH_RENDER, 0));
 
@@ -820,6 +820,21 @@ void opengl_shader_set_passthrough(bool textured, bool alpha, vec4 *clr, float c
 		Current_shader->program->Uniforms.setUniform4f("color", 1.0f, 1.0f, 1.0f, 1.0f);
 	}
 
+	if (clip_plane.enabled) {
+		Current_shader->program->Uniforms.setUniformi("clipEnabled", 1);
+
+		vec4 clip_equation;
+		clip_equation.xyzw.x = clip_plane.normal.xyz.x;
+		clip_equation.xyzw.y = clip_plane.normal.xyz.y;
+		clip_equation.xyzw.z = clip_plane.normal.xyz.z;
+		clip_equation.xyzw.w = -vm_vec_dot(&clip_plane.normal, &clip_plane.position);
+
+		Current_shader->program->Uniforms.setUniform4f("clipEquation", clip_equation);
+		Current_shader->program->Uniforms.setUniformMatrix4f("modelMatrix", GL_model_matrix_stack.get_transform());
+	} else {
+		Current_shader->program->Uniforms.setUniformi("clipEnabled", 0);
+	}
+
 	Current_shader->program->Uniforms.setUniformMatrix4f("modelViewMatrix", GL_model_view_matrix);
 	Current_shader->program->Uniforms.setUniformMatrix4f("projMatrix", GL_projection_matrix);
 }

code/graphics/opengl/gropenglshader.h

@@ -14,6 +14,7 @@
 #include "globalincs/pstypes.h"
 #include "graphics/2d.h"
 #include "graphics/opengl/gropengl.h"
+#include "graphics/material.h"
 #include "ShaderProgram.h"
 
 #include <string>
@@ -166,7 +167,7 @@ void opengl_shader_compile_deferred_light_shader();
 void opengl_shader_compile_deferred_light_clear_shader();
 
 void opengl_shader_compile_passthrough_shader();
-void opengl_shader_set_passthrough(bool textured = true, bool alpha = false, vec4* clr = NULL, float color_scale = 1.0f);
+void opengl_shader_set_passthrough(bool textured = true, bool alpha = false, vec4* clr = NULL, float color_scale = 1.0f, const material::clip_plane& clip_plane = material::clip_plane());
 void opengl_shader_set_passthrough(bool textured, bool alpha, color *clr);
 
 #define ANIMATED_SHADER_LOADOUTSELECT_FS1	0

code/graphics/opengl/gropengltnl.cpp

@@ -796,7 +796,9 @@ void gr_opengl_set_clip_plane(vec3d *clip_normal, vec3d *clip_point)
 	if ( clip_normal == NULL || clip_point == NULL ) {
 		GL_state.ClipDistance(0, false);
 	} else {
-		Assertion(Current_shader != NULL && Current_shader->shader == SDR_TYPE_MODEL, "Clip planes are only supported by the model shader!");
+		Assertion(Current_shader != NULL &&
+				  (Current_shader->shader == SDR_TYPE_MODEL || Current_shader->shader == SDR_TYPE_PASSTHROUGH_RENDER),
+				  "Clip planes are not supported by this shader!");
 
 		GL_state.ClipDistance(0, true);
 	}
@@ -863,10 +865,6 @@ void opengl_tnl_set_material(material* material_info, bool set_base_map)
 
 	opengl_shader_set_current(shader_handle);
 
-	if ( Current_shader->shader == SDR_TYPE_PASSTHROUGH_RENDER ) {
-		opengl_shader_set_passthrough(base_map >= 0, material_info->get_texture_type() == TCACHE_TYPE_AABITMAP, &clr, material_info->get_color_scale());
-	}
-
 	GL_state.SetAlphaBlendMode(material_info->get_blend_mode());
 	GL_state.SetZbufferType(material_info->get_depth_mode());
 
@@ -894,6 +892,14 @@ void opengl_tnl_set_material(material* material_info, bool set_base_map)
 		gr_opengl_set_clip_plane(NULL, NULL);
 	}
 
+	if ( Current_shader->shader == SDR_TYPE_PASSTHROUGH_RENDER ) {
+		opengl_shader_set_passthrough(base_map >= 0,
+									  material_info->get_texture_type() == TCACHE_TYPE_AABITMAP,
+									  &clr,
+									  material_info->get_color_scale(),
+									  material_info->get_clip_plane());
+	}
+
 	if ( set_base_map && base_map >= 0 ) {
 		float u_scale, v_scale;
 

code/graphics/opengl/gropengltnl.h

@@ -33,6 +33,7 @@ extern float shadow_middist;
 extern float shadow_fardist;
 extern bool Rendering_to_shadow_map;
 
+extern transform_stack GL_model_matrix_stack;
 extern matrix4 GL_view_matrix;
 extern matrix4 GL_model_view_matrix;
 extern matrix4 GL_projection_matrix;