Wide lines + line stipple deprecated API replacement

The patch contains an implementation of the wide lines and the line stipple that is necessary for OpenGL upgrade.

For the implementation I have chosen the geometry shader because it required minimum changes for the wrapper calls and such implementation is the best for the "basic shader" architecture.

There are few shortcomings that can be corrected in future. They all are related to the fact that the lines in one strip are not connected with each other. So the stipple pattern is not continuous on the common vertex of two lines. There is also no continuity of form (each line is an independent rectangular).
But the advantage is that even outdated glBegin, glVertex work! Though with the above restrictions.
Continuity of form and stipple can be implemented with additional attributes, and it will require more changes in calls.

At the moment, the patch replaces calls for some "gestures". It works satisfactorily for "cross" or "rectangular" and not so good for "lasso" and "circle" due to the above-mentioned shortcomings.

Don't forget to set USE_GLSL to true for testing.

Alexander Romanov (Blend4Web Team)

Reviewers: merwin, brecht

Reviewed By: merwin, brecht

Subscribers: aligorith, Evgeny_Rodygin, AlexKowel, yurikovelenov

Differential Revision: https://developer.blender.org/D1880

1 files changed, 58 insertions, 7 deletions

diff --git a/source/blender/gpu/intern/gpu_basic_shader.c b/source/blender/gpu/intern/gpu_basic_shader.c
index 4a27965aee1..abaf1944302 100644
--- a/source/blender/gpu/intern/gpu_basic_shader.c
+++ b/source/blender/gpu/intern/gpu_basic_shader.c
@@ -61,6 +61,8 @@ static struct {
 
 	int lights_enabled;
 	int lights_directional;
+	float line_width;
+	GLint viewport[4];
 } GPU_MATERIAL_STATE;
 
 
@@ -325,6 +327,8 @@ static GPUShader *gpu_basic_shader(int options)
 	/* glsl code */
 	extern char datatoc_gpu_shader_basic_vert_glsl[];
 	extern char datatoc_gpu_shader_basic_frag_glsl[];
+	extern char datatoc_gpu_shader_basic_geom_glsl[];
+	char *geom_glsl = NULL;
 	GPUShader *shader;
 
 	/* detect if we can do faster lighting for solid draw mode */
@@ -347,7 +351,10 @@ static GPUShader *gpu_basic_shader(int options)
 			strcat(defines, "#define USE_TEXTURE\n");
 		if (options & GPU_SHADER_STIPPLE)
 			strcat(defines, "#define USE_STIPPLE\n");
-
+		if (options & GPU_SHADER_LINE) {
+			strcat(defines, "#define DRAW_LINE\n");
+			geom_glsl = datatoc_gpu_shader_basic_geom_glsl;
+		}
 		if (options & GPU_SHADER_SOLID_LIGHTING)
 			strcat(defines, "#define USE_SOLID_LIGHTING\n");
 		else if (options & GPU_SHADER_LIGHTING)
@@ -356,7 +363,7 @@ static GPUShader *gpu_basic_shader(int options)
 		shader = GPU_shader_create(
 			datatoc_gpu_shader_basic_vert_glsl,
 			datatoc_gpu_shader_basic_frag_glsl,
-			NULL,
+			geom_glsl,
 			NULL,
 			defines, 0, 0, 0);
 		
@@ -377,6 +384,15 @@ static GPUShader *gpu_basic_shader(int options)
 	return shader;
 }
 
+static void GPU_basic_shader_uniform_autoset(GPUShader *shader, int options)
+{
+	if (options & GPU_SHADER_LINE) {
+		glGetIntegerv(GL_VIEWPORT, &GPU_MATERIAL_STATE.viewport[0]);
+		glUniform4iv(GPU_shader_get_uniform(shader, "viewport"), 1, &GPU_MATERIAL_STATE.viewport[0]);
+		glUniform1f(GPU_shader_get_uniform(shader, "line_width"), GPU_MATERIAL_STATE.line_width);
+	}
+}
+
 /* Bind / unbind */
 
 void GPU_basic_shader_bind(int options)
@@ -385,8 +401,10 @@ void GPU_basic_shader_bind(int options)
 		if (options) {
 			GPUShader *shader = gpu_basic_shader(options);
 
-			if (shader)
+			if (shader) {
 				GPU_shader_bind(shader);
+				GPU_basic_shader_uniform_autoset(shader, options);
+			}
 		}
 		else {
 			GPU_shader_unbind();
@@ -424,10 +442,19 @@ void GPU_basic_shader_bind(int options)
 			glDisable(GL_TEXTURE_2D);
 		}
 
-		if (options & GPU_SHADER_STIPPLE)
-			glEnable(GL_POLYGON_STIPPLE);
-		else if (bound_options & GPU_SHADER_STIPPLE)
-			glDisable(GL_POLYGON_STIPPLE);
+		if (options & GPU_SHADER_LINE) {
+			if (options & GPU_SHADER_STIPPLE)
+				glEnable(GL_LINE_STIPPLE);
+			else if (bound_options & GPU_SHADER_STIPPLE)
+				glDisable(GL_LINE_STIPPLE);
+		}
+		else {
+			if (options & GPU_SHADER_STIPPLE)
+				glEnable(GL_POLYGON_STIPPLE);
+			else if (bound_options & GPU_SHADER_STIPPLE)
+				glDisable(GL_POLYGON_STIPPLE);
+		}
+
 	}
 
 	GPU_MATERIAL_STATE.bound_options = options;
@@ -592,3 +619,27 @@ void GPU_basic_shader_stipple(GPUBasicShaderStipple stipple_id)
 		}
 	}
 }
+
+void GPU_basic_shader_line_width(float line_width)
+{
+	if (USE_GLSL) {
+		GPU_MATERIAL_STATE.line_width = line_width;
+		if (GPU_MATERIAL_STATE.bound_options & GPU_SHADER_LINE) {
+			glUniform1f(GPU_shader_get_uniform(gpu_basic_shader(GPU_MATERIAL_STATE.bound_options), "line_width"), line_width);
+		}
+	}
+	else {
+		glLineWidth(line_width);
+	}
+}
+
+void GPU_basic_shader_line_stipple(GLint stipple_factor, GLushort stipple_pattern)
+{
+	if (USE_GLSL) {
+		glUniform1i(GPU_shader_get_uniform(gpu_basic_shader(GPU_MATERIAL_STATE.bound_options), "stipple_factor"), stipple_factor);
+		glUniform1i(GPU_shader_get_uniform(gpu_basic_shader(GPU_MATERIAL_STATE.bound_options), "stipple_pattern"), stipple_pattern);
+	}
+	else {
+		glLineStipple(stipple_factor, stipple_pattern);
+	}
+}